The marine Mollusca obtained during the Scottish National Antarctic Expedition of s.s. Scotia are particularly interesting, not merely on account of certain benthal forms having been for the first time brought to light from unusual depths, but also as demonstrating an extended geographical range for certain meridional species already known; while the occurrence of sundry British and North European individuals in the Falkland Islands—perhaps brought there adventitiously—is, to some extent, a new feature in the fauna. Regarding the deep-sea species just alluded to, the dredging of a second example of the hitherto unique Guivillea alabastrina, Watson, from a station not far from the original Challenger locality, is very noteworthy; while we may at the same time signalise a Columbarium, Cuspidaria, Chrysodomus, and Dentalium, from 1775, 2645, 1775, and 1410 fathoms respectively.