OCR Text |
Show 1894.] ECHINODERMS OF MACCLESFIELD BANK. 411 SALMACIS RUFA, sp. nov. (Plate XXVI. figs. 2 & 3.) There are several specimens of what I take to be an undescribed species of Salmacis. It may be diagnosed as follows :- Spines pale whitish, with red rings or bands of inconstant breadth. Denuded test bright red, with patches of white more numerous within than between the poriferous zones. Test rather flat, not stout, circular, with a rather small mouth distinctly depressed. Primary tubercles small and numerous ; only one row in each vertical set of plates extends from pole to pole, but at and below the ambitus each plate has a transverse row of four or five tubercles in the interambulacral and of two or three in the ambulacral areas. There are about 27 primary tubercles in a row in a specimen measuring 32 mm. in diameter. The anal area is chiefly occupied by a few large plates ; the madreporite is of proportionately large size, and the ' oculars' are ordinarily shut out from the edge of the anal space. The edge of the mouth is deeply inflexed, and the cuts are wide but not very deep. In a specimen in which the lantern of Aristotle was examined, the teeth were found to project very little from the alveolus; this was stout and wide, with two deep grooves, and had the tooth connected with it by a descending but not by an ascending process. The apophysis is almost straight. Diameter of Diam. Height. Oalyc. area. Periproct. Peristome. 32 mm. 16 6-5 2-5 8-5 Hab. Macclesfield Bank, between 30 and 44 fms. It is a somewhat difficult matter to suggest what are the nearest allies of this species; although the characters just enumerated appear to be constant for the fairly large number of examples which were collected, none of them are of large size, and, possibly, better grown specimens will throw more light on this question. TRIPNEUSTES GRATILLA. Echinus gratilla, Linn. Syst. Nat. x. (1758) p. 664. Tripneustes gratilla, Loven, Bih. Svensk. Vet.-Akad. Hdlgr. xiii. iv. no. 5 (1887) p. 77. An interesting young example of this species was taken in 30-40 fms.; its proportions are somewhat different to the smallest specimen I was able to measure some years since (see P. Z. S. 1879, p. 662). Percentage value of ' --* ^ Absol. diam. Height. Abact. Anal Act. Porif. zone. in millim. system. system, system. 28 69 23 12-5 30 8-2 LAGANUM DECAGONALE. (Plate XXVI. figs. 4 & 5.) Scutella clecagonalis, de Bl. Diet. Sci. Nat., s. v. Scutella, p. 229. A fine series of this species, commencing with specimens less |