204 Prof. C. Semper on the Anatomy o/'Comatula. 



the outer periphery ; but here its connexion with the central 

 cord was not brought into view. On the contrary the peri- 

 pheral layer of the central cord clearly passes into the mass of 



Fiff. 1. 



C.t-.. 



Fig. 2. 



Fig. 1. Transverse section of a decalcified Arm : a, organic basis of the 

 skeleton ; n, cord occupying the canal of the calcareous segment, 

 regarded by Muller as a vessel and by Carpenter as a nerve; 

 m, muscles ; c.c, inferior or cceliac canal ; r, cord regarded by Midler 

 as a nerve, by Carpenter and Semper as the rhachis of the generative 

 system ; ov, ovary ; c.t, superior canal, the tentacular canal of Muller ; 

 x, fibrous cord of Perrier and Semper, corresponding in situation 

 with the real tentacular canal of Carpenter. 



the left ovary. The ova here, as well as in the pinnules, show 

 a distinct germ-vesicle and spot. Muller has seen these con- 

 necting branches, as is shown in the representation of what he 

 calls the nervous cord (l. c. pi. v. f. 16) ; he interprets them as 

 lateral nerves for the pinnules. Judging from the figure, these 

 branches appear to be very fine ; so that, without making sec- 

 tions, Muller might the more readily fail to demonstrate the 

 connexion with the ovaries, as no similar relation in any 

 Echinoderm had given a hint of so peculiar an arrangement 

 of the parts of generation. In what manner these central cords 

 (probably comparable to the rhachis in the ovary of the Nema- 

 toda) are distributed in the disk I have not investigated ; 

 Muller, however, states, and Carpenter has confirmed it to me, 

 that they are traceable far up the disk and there form a ring 

 round the oesophagus. 



