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Show 406 PROF F. JEFFREY BELL ON THE [May 1, to me to be fully justified in regarding Asterias volsellata as a that the difference between the Asteriidae and Brisingidae is not so great as has been generally supposed. If I do not accept his view of the origin of the latter family, it is only because m y capacities are not sufficient for m e to be able to understand how it has been possible for " complete isolation " to have had an " action " on them. O n this point I, and I believe many others, would be glad of a more detailed explanation. The " type " is said to have come from 95 fms., and M r . Bassett- Smith's example from 45 fms. IV. OPHIUEOIDEA. PECTIJTURA SPHENISOI, sp. nov. (Plate XXV. figs. 7-9.) This species stands with P. spinosa, P. arenosa, P. infernalis, and P. heros, of M r . Eyman's arrangement, and P. capensis, Bell; for it has the disc covered under its granulation with coarse scales (much coarser than in P. capensis), and there are no pores between the under arm-plates. There are five or six short arm-spines and two tentacle-scales. Eadial shields not constant, but the typical arrangement probably is that they are small, naked, triangular, and separated from one another by a third triangular plate. The granulation of the disc is coarse, and the peripheral plates large. The arms are not wider at their base than at some distance outside the disc, nor carinated; accessory mouth-shields moderate in size, irregularly oval or quadrate. Six quite short arm-spines; fourteen mouth-papillae. As often is the case the outermost is by far the smallest, and the penultimate distinctly the largest of the series. Mouth-shields almost triangular ; granulated space between mouth-papillae and shield well-marked. The side arm-plates encroach on both the upper and lower surfaces; the upper arm-plates are wider distally than proximally, and the lower are irregularly hexagonal. Ground-colour, when drying, greyish, with brown patches on disc and regular bands of brown extending over three or four joints on upper surface; lower surface uniformly pale. Diam. of disc 5-5 m m . ; length of arm about 40 m m . Holothuria Bank, 15 fms. PECTINURA ELEGANS, sp. nov. This species belongs to Mr. Lyman's second division; but differs from all in having no pores between the under arm-plates. There are six rather short, moderately stout arm-spines and two tentacle-scales. Eadial shields naked, quite distinct, moderate in size, darker than the rest of the test ; granulation rather fine, similar over the whole of the dorsal surface of the disc. The arms taper very gradually from their base; accessory mouth-plates small, semi- |
