the Mor-phology of the Echinoderms. 119 



figures fully bear out, that the pore-canals of the madreporite 

 lead into the water-vascular apparatus only, and have abso- 

 lutely no connexion with the blood-vascular system *. 



These statements have never been contradicted by Professor 

 Perrier, who has nowhere described any such communication 

 between the water- vascular and blood-vascular systems of a 

 Starfish as he believes to exist in Urchins and Crinoids. 



But all the same, he places the Starfishes, together with the 

 other Echinoderms, in the same division of the Metazoa as 

 the Polypes and Sponges. The bodies of the animals com- 

 posing this group, which he calls " Zoophytes," are traversed 

 by a set of irrigating canals f — " H contient de meme, non 

 pas de sang, mais de I'eau qu'il puise incessamment au dehors 

 et se substitue tout a la fois k I'appareil circulatoire et h, 

 I'appareil respiratoire des animaux mobiles, a la sym^trie 

 bilaterale, avec lesquels il n'a aucun rapport morphologique. 

 On doit remarquer que, chez les echinodermes, il derive au 

 moins indirectement de la cavity digestive primitive." 



This conception of the mode of nutrition of Echinoderms 

 is well described by Prof. Perrier as both " simple and new ;" 

 but he can scarcely expect it to be adopted by other naturalists 

 until he can demonstrate to their satisfaction the fundamental 

 unity of the double vascular system and its communication 

 with the exterior not only in Echini, Ophiurids, and Crinoids, 

 but also in Starfishes and Holothurians, about which groups 

 he has given us no positive information at all. 



My own observations have led me to believe that the state- 

 ments which he has permitted himself to make concerning 

 the presence of excurrent openings in the arms of Stalked 

 Crinoids are absolutely without any foundation of anatomical 

 fact. But they harmonize with his theories of Crinoid mor- 

 phology in a way which leaves nothing to be desired for 

 completeness ; and I have a strong suspicion that some of his 

 other assertions respecting the vascular system of the Echi- 

 noderms are equally untrustworthy, as, indeed, has been 

 already proved by Koehler. Other investigators are at work 

 upon the subject, and we may hope to hear a good deal about 

 it before many months are past. 



* ** Beitrage zur Auatomie der Asteriden/' Zeitschr. f. wiss. Zool, 

 Bd. XXX. 1878, p. 104. 



t 'Revue Scientifique,' May 30, 1885, p. 692. 



