No CrossRef data available.
Article contents
Palæontological Notes on the Brachiopoda
Published online by Cambridge University Press: 17 March 2016
Extract
In our second group are provisionally assembled a number of Tere-bratula-shaped species, with a curved hinge-line, no defined area, beak entire, or truncated by a circular foramen for the permanent or temporary passage of a peduncle, and with spiral appendages directed outwards, as in Spirifera, but connected by a more complicated system of lamellæ. Much has, however, to be discovered concerning the interior details of the larger number of the species before we can hope to establish permanent and satisfactory divisions in this group.
The genus Athyris has for years attracted the notice of palæontologists, but it. was not until a recent period that all its important characters could be established. The species vary considerably in their external shape; they are circular or angular, elongated or transverse, smooth, ribbed, or striated, some have the entire surface of their valves covered with numerous concentric plates, which are prolonged in many instances nearly an inch from the surface of the shell, while in other species the valves are covered by a vast number of scaly ridges from which radiate closely-set fringes of elongated, somewhat flattened spines; and so close are these sometimes in their arrangement, that no portion of the shell can be distinguished.
- Type
- Research Article
- Information
- Copyright
- Copyright © Cambridge University Press 1858
References
page 458 note * The term Cleiothyris had been proposed some years before by Professor Phillips for the same kind of shells, but its etymology is liable to the same objection as that of Athyris. On the Continent, the generality of authors refuse to adopt either of these denominations, and prefer that of Spirigera, more recently proposed by D'Orbigny, and I would willingly adopt this last denomination were it not that, both in this particular and many others, naturalists still retain names Which imply zoological contradictions.
page 460 note * The muscular impressions in the interior of the larger valve of Merista are similar to those of Athyris, but we are not perfectly acquainted with those of the other valve. The presence of a hinge-plate is not absolutely required for the insertion of the dorsal pedicle or dorsal adjustor muscles, for Mr. Hancock has observed that “in Waldheimia cranium, and in Terebratulina caput-serpentis, the dorsal adjustor muscles are not attached to a hinge-plate, but are inserted into the valve itself, and that in a species differing but little from W. Australis, the divaricators and accessory divaricators are united.”
page 466 note * A list of these will be found in my Monograph of British Carboniferous Brachiopoda, published by the Palæontographical Society.