Almost all nassellarians possess some skeletons, comprised of cephalic skeletal elements, at the base of their cephalis. Observations using the scanning electron microscope (SEM) have been made on the internal structures of Jurassic “Eucyrtidium” from manganese carbonate ore deposits in the Mino Terrane, central Japan. Jurassic “Eucyrtidium” possesses only a median bar and apical spine as cephalic skeletal elements. Because this structure is quite different from that of Cenozoic Eucyrtidium, which possess MB, A, V, L, l, and D, a new genus, Monosera, is proposed for the Jurassic forms. One new species, Monosera gujoensis, is described.

Representatives of the Ingelarellidae are described from the marine Permian sequences of the Perth, Carnarvon, Canning and Bonaparte Gulf basins of Western Australia. The subfamily Ingelarellinae Campbell (1959) is raised to family status and the new subfamily Notospiriferinae is proposed; content of the Ingelarellidae is reviewed. New taxa described are Tomiopsis notoplicatus n. sp., T. woodwardi n. sp., T. rarus n. sp., T. pauciplicatus n. sp., T. teicherti n. sp., T. globosus n. sp., T. balgoensis n. sp. and T. hardmani n. sp. Additional material from Western Australia belonging to Tomiopsis and possibly Fredericksia is briefly described. Tomiopsis harringtoni n. sp. is described from the southern hills of Buenos Aires (eastern Argentina).

Since Haeckel's Biogenetic Law (‘ontogeny recapitulates phylogeny’) fell into disrepute early in the twentieth century, there has been intermittent debate, particularly in recent years (de Beer, 1958; Gould, 1977; Alberch et al., 1979; Alberch, 1980; Bonner, 1982; McNamara, 1982a), on the nature of the relationship between an individual's development and phylogenetic history. Important questions under discussion include the following: If a strong causal relationship does exist, what is its nature? How does it work? What is its importance in evolution? How can it be recognized in the fossil record?

A diverse, previously unknown fauna with Skenidioides and other small brachiopods, ostracodes, trilobites, and corals has been dated as gronbergi Zone on coexisting conodonts. Conodonts date the Leptocoelina globosa fauna as serotinus Zone. Cymostrophia seca, Strophodonta luxor, and Atrypa kobar are new species. These assignments and new occurrences allow retabulation of most Emsian brachiopod ranges in Nevada.

Plotting of provincial, endemic, and cosmopolitan brachiopod genera on a time vs. percent graph shows that the shift through time of Nevada faunas from Eastern Americas Realm to Old World Realm took place gradually during Emsian transgression. Endemic genera were prominent during early phases of Devonian transgression.

Agglutinated siliceous foraminifera occur in the Middle Ordovician (Blackriveran) Mifflin Formation of the Platteville Group in northern Illinois. The fauna consists of globular saccamminids and a new form Reophax blackriveranus n. sp. which records the oldest validated representative of this genus. This marks the earliest known occurrence of agglutinated foraminifera with multichambered uniserial tests of progressively expanding chambers from the proloculus to the aperture. This early innovation of test morphology was probably developed to control unfavorable changes in the water chemistry of the environment.

Mifflin lithofacies consist of light gray, thin, wavy-bedded, lithographic limestone and fine-grained dolomite with green shale interbeds, thin calcarenite layers with graded bedding, a K-bentonite ash layer and hardground corrosion bedding surfaces. Mifflin biofacies include the foraminiferan fauna, brachiopods and molluscan shelly faunas, bryozoans, trilobites, ostracodes, echinoderms, solitary corals, conodonts, chitinozoans, scolecodonts, sponges and trace fossils particularly Chondrites.

The Mifflin strata were deposited on an exceedingly gentle slope off the Pecatonica carbonate platform which flanked the Wisconsin Arch. Thin Mifflin clinothem limestone beds wedge out into shales in the moderately deep (<200 m) aerobic starved basin in eastern Iowa. This occurred in south tropical seas during a eustatic rise in sealevel and major marine transgression. Reophax is associated with saccamminids in the benthos of the marine upper foreslope. Apparently slope-dwelling Reophax foraminifera of the Ordovician were displaced downslope into the basin by the rapid development and expansion of hyperamminids which occupy the lower and middle foreslope in the Mississippian.

Although Nuculoidea corbuliformis (Hall and Whitfield) is the most widespread Devonian nuculid species in North America, the hinge and internal morphology have not been adequately described. A newly excavated hinge shows the dentition and resilifer to be fundamentally similar to those of other species of Nuculoidea, while the resilifer morphology and shell shape more closely link N. corbuliformis to post-Devonian nuculid species. An internal mold of a probable N. corbuliformis found among Hall's original syntypes (here restudied) shows typical nuculid interior morphology. These new data allow the problematic genus Nuculoidea Williams and Breger to be further clarified.

Comparisons with N. corbuliformis suggest that N. aquisgranensis (Beushausen), N. herzeri (Nettleroth), N. neda (Hall and Whitfield), N. niotica (Hall and Whitfield), N. trigona (Spriestersbach), N. macrorhyncha (Spriestersbach), and N. subtrigona (Simpson) are subjective junior synonyms.

Neotryplasma floweri n. sp. is an epizoic solitary rugose coral characterized by two orders of perforate, monacanthine, carinate septa, a complex axial structure of septal lobes and lamellae, and a well developed broad dissepimentarium. It occurs in the Late Ordovician (late Edenian to earliest Maysvillian; late Caradoc) Upham Dolomite Member of the Second Value Dolomite, Montoya Group, at El Paso, Texas, U.S.A. Neotryplasma Kaljo, 1957, also includes two Late Ordovician species from the Estonian S.S.R. and one from the late Middle and Late Ordovician of the northern and middle Ural region, U.S.S.R. This genus is assigned to the Neotryplasmatidae n. fam., which is placed in the Suborder Monacanthina Neuman, 1984.

Neotryplasma appears to be closest to Sumsarophyllum Lavrusevich, 1971a, from the Late Ordovician of the Zeravshan-Gissar region, U.S.S.R. This is noteworthy because Erina (1978) and Erina and Kim (1980) suggested that the latter may be a scleractinian coral of the Order Fungiida Verrill, 1865. The rugosan mode of septal insertion has been confirmed in Neotryplasma. N. floweri seems to bear close resemblance to a poorly known Ordovician coral, Cyathophyllum (?) kjerulfi Kiaer, 1932, from Caradoc–Ashgill strata in the Trondheim region of Norway.

Fourteen new species and six new genera of the molluscan class Monoplacophora are described from the Upper Cambrian Potosi and Eminence formations and the Lower Ordovician Gasconade Formation of the Ozark Uplift of Missouri and some new biostratigraphic horizons are introduced. A new superfamily, the Hypseloconellacea nom. trans. Knight, 1956, and a new family, the Shelbyoceridae, are named. The genus Proplina is represented by five new species: P. inflatus, P. suttoni from the Cambrian Potosi Formation, P. arcua from the Cambrian Eminence Formation and P. meramecensis and P. sibeliusi from the Lower Ordovician Gasconade Formation. A new genus and species in the subfamily Proplininae, Ozarkplina meramecensis, is described from the Upper Cambrian Eminence Formation. Four new monoplacophoran genera in the superfamily Hypseloconellacea and their species are described, including: Cambrioconus expansus, Orthoconus striatus, Cornuella parva from the Eminence Formation, and Gasconadeoconus ponderosa, G. waynesvillensis, G. expansus from the Gasconade Formation. A new genus in the new family Shelbyoceridae, Archeoconus missourensis, is described from the Eminence Formation and a new species of Shelbyoceras, S. bigpineyensis, is described from the Gasconade Formation.

Lower bathyal sediments representing portions of the Luisian and Mohnian stages of Kleinpell (1938) occur on a submarine ridge near Tanner Bank, offshore southern California. The presence of abundant and well-preserved calcareous nannofossils, diatoms, silicoflagellates, radiolarians and foraminifera allows accurate correlations with the onshore type sections of these stages. In terms of the calcareous nannofossil zones, the age range is from the Sphenolithus heteromorphus Zone to the Discoaster kugleri Zone. Although abundant benthic foraminifera indicative of the Luisian and Mohnian are present, they are accompanied by species more characteristic of the Pliocene Repettian Stage of Natland (1952) and the Pliocene-Miocene “Delmontian” Stage of Kleinpell (1938). Many of these latter species live today at lower bathyal depths (below 2,000 m), others occur in lower bathyal sediments as old as Oligocene, but are absent in the onshore type sections of the Luisian and Mohnian stages in coastal California. We ascribe their absence in onshore sequences to deposition at middle bathyal depths. The known chronostratigraphic ranges of several species are extended and five new species and two new subspecies of benthic foraminifera are described.

The following new taxa are described: Bolivina pelita n. sp., Cassidulinella inflata n. sp., Globocassidulina undulata n. sp., Cibicidoides mckannai miocenicus n. subsp., C. mckannai sigmosuturalis n. subsp., Pullenia fragilis n. sp., Parafissurina inornata n. sp.

The Protocardiinae is represented by 11 valid species of Protocardia and one species of Nemocardium in the Lower Cretaceous of the Gulf of Mexico. These taxa appeared in the Caribbean Province through a combination of immigration and evolution from the local stock. One species group, Protocardia texana-Protocardia salinaensis-Protocardia subspinigera, developed as geographically and environmentally distinct populations that migrated in space and time. Another group, Protocardia roanokensis-Protocardia prosogyrata-Protocardia nutans-Protocardia denisonensis, differentiated through time by dichotomous branching. These species occupied sand to mud substrates. The coarseness of their shell ornament is positively related to substrate grain size. The geographic and stratigraphic distributions of these species illustrate that diversity is positively correlated with the extent of distribution and that endemism develops during transgression.

The small, distinctive, glyptorthinine brachiopod Ptychopleurella Schuchert and Cooper is widely distributed in rocks of early Ordovician to late Silurian age. Several species are known from the Barr and Ardmillan successions (middle-upper Ordovician) of the Girvan district, S.W. Scotland, one of which, ‘Orthis Lapworthi’ Davidson, has not been described in modern terms as there has been some confusion concerning its true identity. Recognition of this species of Ptychopleurella permits comparison with congeners elsewhere, strengthens the correlation of this part of the Girvan Succession with the middle Ordovician of North America, and provides a more complete record of this genus in the slope sedimentary facies of the northwestern margin of the Iapetus Ocean.

“Chiton” carbonarius Stevens, 1858, is reassigned as the type species to Glaphurochiton Raymond, 1910. This species evolved from an unknown Mississippian ancestor, and spread rapidly into the Midcontinent region, Eastern Interior, and Appalachian basins during the Morrowan. Glaphurochiton carbonarius served as the root stock for development of several species: G. concinnus (Richardson) during the Desmoinesian and G. subcircularis n. sp. during the Virgilian in the Eastern Interior basin and G. elimatus n. sp. in the Appalachian basin and possibly G.? riddlei (Frederickson) in the Midcontinent region during the Missourian.

Glaphurochiton is believed to have been essentially restricted to a mud bottom based upon its occurrence and relative abundance. Commonly the only taxon present, often abundantly, in black and gray shales, Glaphurochiton is rare to absent in limestones, algal limestones, reefs, and shales with an abundance of crustose calcareous algae. The latter lithologies commonly support a diverse polyplacophoran fauna essentially lacking Glaphurochiton.

Acidolites Lang, Smith and Thomas occurs in upper Middle and Upper Ordovician, Lower and lower Middle Silurian rocks of Ontario and Quebec. On Anticosti Island, Quebec, the genus is represented by A. tenuis (Billings) in the Upper Ordovician (Gamachian) Ellis Bay Formation; the new species A. arctatus, A. compactus and A. helianthus in the Ordovician–Silurian boundary beds at the top of the Ellis Bay Formation; the new species A. arctatus, A. compactus and A. lindströmi in the lower Llandoverian Becscie Formation; A. arctatus in the mid-Llandoverian Gun River Formation; and an unnamed species in the upper Llandoverian Jupiter Formation. The lower Llandoverian Clemville Formation of the Gaspé Peninsula, Quebec, contains Protaraea clemvillensis Parks, now considered to be Acidolites. The upper Middle to lower Upper Ordovician Cobourg Formation near Ottawa, Ontario, contains A. cf. arctatus, formerly included in Protaraea vetusta (Hall). The lower Wenlockian Amabel Formation in southern Ontario contains a species of Acidolites as yet unnamed.

As first designated by Böse, the Albian-Cenomanian (Lower Cretaceous-Upper Cretaceous) boundary in northern Mexico and Texas is selected at the base of the ammonite zone of Plesioturrilites brazoensis (Römer). This boundary seems to best agree with boundaries selected for North Africa and Europe, but in North America it may not be the optimum boundary for paleontologists working with foraminiferans.

Five new species of mollusks are described from the early Eocene Maniobra Formation, northeastern Orocopia Mountains, southern California. The new species are from the basal part of the formation, and the fauna is indicative of the West Coast provincial molluscan early Eocene “Capay Stage.” The mollusks are shallow-marine forms that were transported a short distance into slope/upper submarine-canyon deposits.

Chedevillia saltonensis n. sp. and Eocypraea? maniobraensis n. sp. resemble Eocene species from Paris Basin, France. Phalium (Semicassis) louella n. sp. is the earliest North American species of Semicassis. Volutilithes orocopiaensis n. sp. is the earliest North American species of this genus and resembles V. muricinus from Paris Basin. Glossus (Meiocardia) susukii n. sp. is the earliest reported species of Meiocardia on the West Coast of North and South America.

Galeodea gallica, a species previously only known from lower Eocene strata in the Anglo-Paris Basin, is tentatively identified from the Maniobra Formation. Campanilopa dilloni, previously only known from south-central California, is present in the formation. Supplementary descriptions and illustrations are given for these two species.

The Maniobra species described have a close relationship to species characteristic of the Eurasian Tethyan paleobiogeographic province. The age of the Maniobra mollusks permits greater resolution of the timing of the westward migration of the Eurasian species, indicating that much of it occurred during early Eocene and/or late Paleocene time.