166 BULLETIN OF THE 



separated from the centrodorsal by a complete circlet of basals, and 

 there are no pinnules upon any of the first six ai-m-joints, which are the 

 only ones preserved. An equally mutilated specimen was dredged by 

 the " Challenger " in 350 fathoms, near Pernambuco, and more perfect 

 ones were obtained off Nevis, St. Lucia, and Grenada during the cruise 

 of the "Blake" in 1878-79 (Stations 150, 151, 222, and 260, depths 

 291-375 fathoms). In most individuals the first pinnule is borne by 

 the 12th arm-joint (Figs. 1, 2), but in one ai'm of one individual it 

 occurs as early as the 10th joint. In no case, however, is there any 

 pinnule on the second brachial. 



This type is one of singular interest. With the exception of the 

 doubtful genus Comaster* no recent Comatida yet known retains its 

 embryonic basals on the exterior of the calyx after the latter part of its 

 existence as a " Peutacrinoid " ; while there is no known Coniatula, either 

 recent or fossil, in which the basal circlet is complete, as it is in some 

 Pentacrmi,+ and in the earlier stages of. the Pentacrinoid larva. 



As regards the characters of its calyx, therefore, this new Comatula 

 may be considered as a permanent larval form. The absence of pinnules 

 from the lower portions of the arms points to the same conclusion ; and 

 it is not a little singular to find these two larval characters (viz. a closed 

 basal circlet and pinnule-less arm-bases) persisting in recent ComatulcB. 

 The combination seems to me sufficiently remarkable to justify the 

 establishment of a new genus, which I propose to call Atelecriiius.\ 



The original specimen from Cuba (Fig. 7) is so different from those 

 obtained later (Figs. 1, 3), that it should, I think, be regarded as a dis- 

 tinct species, and may retain the name cubeusis, originally conferred 

 upon it by Mr. Pourtales. The other species I propose to name bala- 

 noides, in allusion to the peculiar form of its centrodorsal (Figs. 1, 3), 

 which was well described as acorn-shaped by ]\Ir. Pourtales. It may be 

 as much as 5 mm. long by 3^ nun. in diameter, and bears five double 

 rows of cirrhus-sockets, which are separated near its upper end by slight 

 interradial ridges and do not quite reach the dorsal pole. Each socket has 

 a horseshoe-shaped rim which is much more strongly marked in some 

 specimens than in others. The arch of the horseshoe is directed up- 

 wards, and the two ends are frequently turned somewhat upwards and 

 outwards, so that the surface of the centrodorsal has a very rough ap- 

 pearance. This is more marked, however, in Atelecrinus cubeusis (Fig. 7). 



* Journ.Linn. Soc. Zool., Vol. XIII. pp. 45i-156. 

 t Ibid., Vol. XV. pp. 210, 213-215. 

 J dreX^s, incomplete. 



