1884.] 



On the Nervous System of the Crinoidea. 



67 



IV. On the Nervous System of the Crinoidea." By WILLIAM 

 B. CARPENTER, C.B., M.D., LL.D., F.R.S. Received May 20, 

 1884. 



In a Memoir " On the Structure, Physiology, and Development of 

 Antedon (Comatula, Lamk.) rosacea," presented to the Royal Society 

 in 1865, I stated* that I had ascertained that the cord (fig. 1, g) lying 



ftcz 



n 



Diagrammatic transverse section of an arm of Antedon rosacea. (The ventral or 

 ascending branches of the axial cord cannot be followed continuously in any 

 single section.) ax, axial cord, giving off pairs of branches, n, n, which proceed 

 towards the dorsal aspect of the arm ; nm, branches distributed on the ends of 

 the muscular bundles, whose position is marked out by the dotted lines m, m ; 

 na, ventral branches ; cc, coeliac canal ; stc, subtentacular canal ; g, genital 

 rachis ; tc, tentacular canal or water-vessel, giving off branches to the tentacula, 

 t, t, between which lies the ambulacral groove, whose floor i* covered by a thick 

 ciliated epithelial layer, ae, immediately beneath which is the riband-like band, 

 ttc, supposed to be the ventral nerve ; *, s, sacculi. 



* " Philosophical Transactions," 1865, p. 705. 



p 2 



