Morphology q/Antedon rosacea. 39 



page that the fibrous tissue is apoarently elastic or muscular ; 

 but lower down on the same page they definitely speak of the 

 " fibres tres fines du tissu elastique," vvhicli are " isolees et 

 ne se r^unissent pas en faisceaux comme celles des muscles." 

 Their undecided mode of reference to tliese fibres is a point of 

 considerable interest, for Perrier (whom in general the Swiss 

 authors follow through thick and thin) has described them as 

 forming powerful muscles by which water is expelled from 

 the arm -canals through pores at the periphery of the syzygy. 

 The Swiss authors do not in this case use any such form of 

 expression as " Les recherches de M. Edm. Perrier ont com- 

 pl^tement ^lucide cette question ;" but they merely give a 

 quotation from Perrier's statement of his theory without any 

 confirmatory expressions of their own *. 1 have already given 

 my own reasons for not accepting it f, and I am therefore very 

 glad to find that such ardent admirers of Prof. Perrier's re- 

 searches as Messrs. Vogt and Yung have altogether refrained 

 from expressing their belief in it. 



The Swiss authors' description of the vascular system of 

 Coinatula calls for a much more detailed criticism than would 

 be at all possible at present ; but one or two points may be 

 noticed here. Speaking of the structures immediately beneath 

 the ambulacral epithelium, they say on p. 538, " Quelquefois 

 on y voit des ecartements qui ont 6i€ pris pour I'expression 

 d'un vaisseau dit nerveux, dont nous contestons formellement 

 I'existence." Greetf has figured this cavity in the arm of 

 Antedon rosacea X 't and I have seen it over and over again 

 in both arms and disk of this species, as well as in Antedon 

 Eschrichtij Actinometra nigra, A. parvicirra, A. pulchella, 

 and Pentacrinus decorus, and in the arms of Bathycrinus 

 Aldrichtanus. In good sections of the larger types its epithe- 

 lial lining may be seen, as described and figured by Ludwig 

 m Ajitedon Eschrichti ^ ; and if the Swiss authors had fol- 

 lowed his example they would have seen a good deal in the 

 structure of the ambulacra, and more especially in that of the 

 geniial tube, which they have failed to make out in the small 

 arms of Antedon rosacea. 



Considering the very definite character of the intervisceral 

 blood-vessels of this type, those namely which form a plexus 

 interpenetrating the connective-tissue meshwork within the 



* Op. cit. p. 561. 



t " Ud some poiuta in the Morpholog-y of the Echinoderms, and more 

 especially of the Ciinoids," Ann, & Mag. Nat. Hist. 1885, ser. 5, vol. xvi. 

 pp. 110-116. 



X " Ueber den Bau der Crinoideen," Marburg Sitzuugsberichte, 1876, 

 no. 1, p. 20. 



§ Op. cit. p. 267, Taf. xii. fig. 9. 



