336 PROCEEDINGS OF THE ACADEMY OF [1885. 



DORYCRINUS Roemer, Rev. ii, p. 176. 

 Additional species : — 



D. lineatus S. A. Miller, L881, Journ. Cinein. Soc. Nat. Hist. (December), PI. 7, figs. 

 ."., 3 a, from New Mexico, is specifically identical with D. unicornis (0. & Shum.). 



Family VI.— PLATYCRINIDiE Roemer. 



(Emend. W. & Sp.). 



CULICOCRINUS Job. Miiller, Rev. ii, p. 61. 



This genus is known only from casts, and reasonable doubts 

 may be entertained as to the correctness of Mailer's figures. That 

 the whole ventral side had been covered by only five plates, as 

 described by Miiller, seemed to us not very probable, and we sug- 

 gested in our description that perhaps it had been composed of 

 eight pieces : a central plate, 6 proximals and an anal piece, of 

 which the sutures had been obliterated. Of late, however, we are 

 inclined to abandon this view, as the plates in question are too 

 large to be proximals, neither can they be orals, for the larger 

 plate is pierced by the anal opening. It seems to us Culicocrinus 

 represents morphologically a still lower form than even Cocco- 

 crinus, that its ambulacra were subtegminal, and probably also 

 the oral piece, unless this is represented by the tubercle in the 

 larger plate. 



COCCOCRINUS Job. Miiller. Rev. ii, p. 58. 



(Revised). 



In our generic description it was incorrectly stated that Cocco- 

 crinus had but a simple interradial to each side. This was partly 

 due to a misunderstanding of the plates. The first range consists 

 of three pieces, as clearly shown in Coccocrinus bacca Roemer 

 (Silur. Fauna West Tenn., PI. 4, fig. 5 c). The middle plate, the 

 one we described, rests within the notch of two first radials, the 

 other two against the upper face of one of them, and against the 

 second and third radials. A fourth plate, which we previously 

 described as an oral plate, but which we regard now a secondary 

 interradial, abuts against the upper faces of the three former. 

 The plates of adjoining interradii do not touch laterally, but are 

 separated by a very regular linear cleft, which extends all the way 

 from the central gap to the arm furrows. There are nowhere 



