352 PROCEEDINGS OF THE ACADEMY OF [1888. 



of the centro-dorsal in some species of Antedon is almost identical 

 with that of the top stem joint of Mi Her icrijius ; the plate is also 

 interradial (PI. 6, fig. 11), and i-ests, as in the Apiocrinidae, against 

 the outer face of the basals, not within the basal ring. It is similar, 

 in other Comatulae, in all of which the centro-dorsal is interradial, 

 and upon this, mainly, we base the opinion that perhaps also the 

 Comatulae in their early larva had rudimentary underbasals. That 

 these plates if present were not observed, is not surprising, as they 

 may have been very minute, and been covered entirely by the 

 column." 



So strongly were we impressed with the conviction that the Com- 

 atulae were dicyclic crinoids, that we urged European investigators 

 to make a fresh search for the underbasals in the larva, notwith- 

 standing that no trace of them had been found by Wy ville Thomson, 

 the two Carpenter, Gotte and others, who had extensively studied 

 the embryology of Antedon. 



It was therefore with no little satisfaction that we received the 

 information in July 1887 that the underbasals, whose existence we 

 had thus predicated upon palaeontological evidence, had actually 

 been discovered in the early larva of Antedon rosacea. This import- 

 ant discovery was made by Mr. H. Bury, who announced it at the 

 Manchester Meeting of the British Association in 1887. Mr. Bury's 

 paper giving the full details of his investigations, has not yet appeared, 

 although understood to be in press. The results, however, are stated 

 by Carpenter^ as follows : " while this paper was in press an important 

 discovery was announced by Mr. H. Bury at the Manchester Meeting 

 of the British Association. He has found the underbasals in the 

 ciliated larva of Antedon rosacea: but they soon fuse with the top stem 

 joint (centro-dorsal), and all trace of them is lost when the cirri 

 appear. This is a very striking confirmation of the views of Messrs. 

 Wachsmuth and Springer, whose palaeontological studies had led 

 them to express the belief that the underbasals might be present in 

 the early larva of Comatulae. " 



Upon the same grounds, we think, we may safely postulate a 

 dicyclic base in the extensive families of Apiocrinidae and Pentacrin- 

 idae, and all other Neocrinoid families in which the so-called centro- 

 dor,sal or top stem joint is described as forming an integral ])art of 

 the calyx as in the Comatulae, and whose stem, when angular, is 



' Notes on Echinodeim Morphology, No. XI, Quart. Journ. Microscop. Sci., 

 Vol. XXVIII, New. Sen p. 311. 



