the Morphology of the Echinoderms. Ill 



while in the case of BMzocrinus one has still more difficulty 

 in accepting Prof. Perrier's theory. For there are only five 

 water-pores, at any rate in R. lofotensis ; and though there 

 are sygygies on the arms, their outlines are not marked by 

 anything like pores, as is the case in the Gomatulce. As Prof. 

 Perrier has plenty of iSA^^(9cm^MS-material at his command it 

 is a little surprising that he should have committed himself 

 to a general statement of this kind, which is so far from being 

 in accordance with the actual facts of the case. The absence 

 of the slri^, which are so characteristic of the syzygial faces 

 of the ComatulcBy on the corresponding faces of the arm -joints 

 of UMzocrinus was noted by Sars * ; and without striee there 

 can be no pores. This observation was confirmed in the 

 * Challenger ' Report ; and it was also pointed out that the 

 closeness of the syzygial union is increased by tliere being a 

 small pit in the hypozygal which receives a backward process 

 on the lower surface of the epizygalf. It will puzzle Prof. 

 Perrier to discover, even with what his colleagueMons. Koehler 

 calls " the eye of faith," any appearance of pores round the 

 outline of a syzygial union in Uliizocrinus. The condition of 

 the two living genera of the Bourgueticrinidse, therefore, is 

 far from being such as is implied by Prof. Perrier's very 

 general statement ; and lie will find some difficulty in recon- 

 ciling it with his " simple and new " conception of the mode of 

 nutrition of the Crinoids. Let us see how far his statement is 

 applicable to other genera of " Encrines " or Stalked Crinoids. 

 He has never seen the arms of HyocrinuSj but apparently 

 takes for granted the presence of syzygial pores, such as he 

 believes to exist in the Gomatulce. I have not been able to 

 examine one of the syzygial faces in an arm-joint of this genus, 

 but there is no external indication of the presence of any 

 radiating markings such as occur in the Gomatulce. The lines 

 of syzygial union are perfectly continuous and uninterrupted, 

 as is well shown in the figures published by Sir Wyville 

 Thomson in 1876 % and reproduced in pi. vi. of the ' Chal- 

 lenger' Report. 



Here, then, is a third " Encrine " to which Prof. Perrier's, 

 statement and theory do not apply ; and he fares no better in ' 

 the case of Holopus. If there are any syzygial unions in the 

 skeleton of this type at all they only occur between the two 

 outer radials, and it is extremely doubtful if such is the case. 

 At any rate, however, the apparent lines of syzygial union 

 have no indication of possible pores, as is the case in the 



* ' Crinoides vivants,' p. 22. 



t Zool. Chall. Exp. part xxxii. pp. 5, 2.54, pi. x. 6gs. 1, 6, 8,17-19. 



i Journ, Linn. Soc, Zool. yol. xvi. pp. 51, 5^. 



9* 



