KONGL. SV. VET. AKADEMIKNS HANDLINGAR. BAND. 19. N:0 7. 



()5 



aspect, and distinct from the interradia by a faint linear impression, discernible in the 

 largest of the specimens examined onl}'; above it the calyx is slightly raised. The central 

 ossicle, or what may have filled its place, is lost, and a nearly pentagonal open space is 

 left in the centre, or rather anteriorly. The live costals are very large, the posterior one, 5, 

 somewhat smaller than the othei's; they are all hexagonal, with the outward side slightly 

 truncated for the reception of the narrow middle plate of the corresponding interradium. 

 The costals 1 and 3 each bear a slightlv tubular pore, apparently sexual, placed towards 

 the inner margin. Water-pores were not to be found. The radials are pentagonal, eacli 

 contiguous to the top of an ambulacrum; there is no trace of an ocular pore, if this be not 

 marked by a slightly larger granule observable in two or three of them. The whole 

 calyx is covered with a dense granulation similar to that of the interradia, but without 

 any indication of linear arrangement. The whole, costals and radials, appears as if 

 of one piece, the sutures being excessively fine, and to be elicited only by the treat- 

 ment mentioned above. The relative magnitude of the entire 

 system, the prominent share it takes among the constituents of 

 the skeleton, the forms and proportions of its parts, are such as 

 forcibly to recall the calyx of some Palasocrinoid, and to justify 

 a desire to turn the Echinoid upside down and to see the 

 calycinal system in its imaginary original position, when it form- 

 ed a part of some remote ancestral type. In this aspect the 

 resemblance becomes still more striking. 



In the remarkable group of the Saleniada?') the three con- 

 stituents of the calycinal system, the central pentagon, the i'i«'-echinus princeps Laube, with 



-' . ""^ u'o""' upwards. 



costals, and the radials, are all simultaneously persistent in the 



adult. The madreporite, the sexual openings, and the organs of vision, are in pos- 

 session of their respective ossicles. The system is generally seen to expand largely, 

 covering a great extent of the dorsal surface, and to exhibit, in forms of Mesozoic 

 existence, a highly elaborate sculpture, repeating almost every characteristic observed in 

 the calyx of Crinoids of preceding, Palaeozoic, ages, but apparently of none from later 

 times, as though in token of a common descent, and a yet not very remote epoch of 

 separation. The granulation seen in Acrosalenia, the deep impressions crossing the 

 sutures in Peltastes, the strong straight ridges connecting the centres of the ossicles 

 in Goniophorus, the impressed points at their sutures and angles in Salenia, often 

 continued on either side into parallel lines, are features well known in the PaliBocri- 

 noidea and present also in the Cvstoidea, but evanescent in the Crinoidea of Secondary 

 and later ages. 



In the oldest of the known genera, Acrosalenia^), the periproct at first but 

 slightly touches the central disk or even fails to attain it. Placed closely Avithin the po- 

 sterior margin of the costal 5, its large aperture is widened lengthwise, sometimes leav- 



') Etudes, p. 27, 70, 78, pi. XIX, fiij. 177; XXI. 



-) It is hardly necessary to mention that the figures here given are taken from the works of M. Cotte.\u 

 in the "Palcontologie Fran^aise" and elsewhere, all unsurpassed models of research and elucidation. 



K. Sv. Vet. Vkn.l Hiin.lL B.-iiid \'.l X;o 7 9 



