ON THE TEST OF THE TEMNOPLEUEID^. 343 



any. Colour porcellaueous. Spire very short, roundedly conical, 

 subscalar from the cylindrical rise of the whorls out of the per- 

 pendicularly sunk sutural channel. Apex very blunt and rather 

 large, impressed. Whorls 5, very short, except the last, whicli 

 occupies nearly the whole shell, rounded above, cylindrical below 

 in the channel of the suture, which is axially impressed. Mouth 

 oblong, pointed and channelled above, slightly narrowed below. 

 Outer Uj) thin, scarcely prominent or arched, running out to a 

 blunt point in front to the right, whence it is obliquely truncated 

 backwards to the point of the pillar with a deepish cut. Inner 

 Uj} : there is on the body a very thick prominent and irregular 

 pad of glaze, which curves round the straight point of the pillar 

 and there is 4-plaited, and, with a sharply defined edge, encircles 

 the point of the shell. H. 0-26. B. 0-13. Penultimate whorl, 

 height 0-035. Mouth, height 0-19, breadth 0-07. 



The low spire, very blunt apex, and four plaits on the pillar- 

 pad distinguish this species from O. rosalina, Duclos, or 0. ruji- 

 fasciata, Reeve (which Dr. Kobelt holds as = O. mutica, Say), or 

 O. inconspicua, C. B. Ad. It is perhaps most like O. pusilla, C. 

 B, Ad., which it resembles in lowness of spire and angularity at 

 suture ; but the spire is even lower than in that species, and the 

 body-whorl is more tumid. 



On some Points in the Morphology of the Test of the Temnopleu- 

 rid^e. By Prof P. Maetin Duncan, M.B. Lend., P.E.S. 



[Read December 15, 1881.] 



(Plate VIII.) 



Contents : — I. Introductory Remarks on the Subfamily Temnopleuridce. 

 II. Morphology of the Pits of Salmacis sulcata, Agass. III. The 

 Sutures of Salmacis sulcata. IV. The Morphology of the pits, 

 sutural marginal grooves, and of the sutures of Adult Tenmopleurus 

 loreumaticus, Agass., and of the Young form. V. The Pits and Sutures 

 of Salmacis bicolor and Amblypneustes ovum. VI. Remarks on the 

 pits, sutural grooves, and sutures. VII. Classificatory Conclusions, 



I. Introchictory Remarks on tlie Temnopleuridre. 

 Desok, in his ' Synopsis des Echiuides Fossiles ' (1858), divided 

 his tribe of Latistellate Eegular Echini into the Oligopores and 

 Polypores ; and he separated the Oligopores— that is to say, the 

 Echini with three pairs of pores to each ambulacral plate — into 



