ECHINODERMS. 129 
the spaces between the rays. In the discitorm genus Culcita, the 
appendages of the rectum are greatly developed, five in number, 
each divided into two branches, and clustered’. In Ophiura and 
Luryale the cecal stomach has lateral recesses, or even branched 
blind appendages, mostly ten in number, which, however, do not 
penetrate the rays. In Comatula the intestinal canal is tubular, 
and winds round a spongy structure in the axis of the disc; from 
this an edge projects, that penetrates into the canal and forms a 
valve”. In the sea-urchins (Hchinus) the intestinal canal is very 
long. The cesophagus is tortuous, narrow, and beset with numerous 
follicles. Where it passes into the much wider intestinal canal, 
there is a cecal appendage. The walls of the canal are very thin: 
its course is close to the shell in five ares directed outwards; when 
it has returned nearly to the point from whence it began, it bends 
round and follows a similar route in an opposite direction, until at 
last, having become somewhat narrower, it mounts up to the anus 
(at the uppermost part of the shell). In the Holothurie the intes- 
tinal canal is nearly of the same width throughout. It proceeds 
from the mouth along one side of the body to the lower extremity, 
then bends back to the anterior part, and finally descends along the 
other side to the cloaca, into which the respiratory organs also 
open. In Echiurus the intestinal canal is, in like manner, much 
longer than the body, and makes many convolutions: it has numer- 
ous cystiform widenings, and very thin walls. In Sipunculus, 
where the anus is placed not at the end, but in the anterior half of 
the body, the intestinal canal, with its threefold bending, is nearly 
four times the length of the body. In Synapia, on the other hand, 
it is nearly straight, and about the length of the body, the anus 
being at the posterior extremity*. In the star-fishes probably the 
radiating appendages are to be considered as organs for preparing 
bile (liver): they are filled in Ast. rubens with a yellow turbid 
fluid *. 
1 J. MUELLER und F. H. TroscHe, System der Asteriden. Braunschweig, 1842, 
4to, 8. 132. Taf. XII. fig. 1. 
2 J. Mueuusr, Abhandl. der Berl. Akad. a. d. J. 1841, Physik. Kl. Tab. v. f. 7—10. 
3 QUATREFAGES, Ann. des Sc. nat. sec. série XV1., Zooloyie, p. 51. 
4 Other writers consider the blind appendages at the bottom of the stomach or at 
the rectum as a rudiment of liver. Ownrn, Lect. on the Comp. Anat. of wmvertebr. 
Animals, 1843, p.115. In these appendages a rudimentary form of kidney might also 
be recognised, an opinion, however, which does not rest on chemical investigation. 
MOL: I. g 
