384 P. HERBERT CARPENTER. 



ont 6te deposees, et leur developpement n'est pas eacore com- 

 plet que les divers articles de la pinnule sont deja parfaite- 

 raent distincts ;" while he described their development in the 

 following terms : — " D'apres ces observations, il semble que la 

 premiere portion formee est le noyau de chaque vesicule ; 

 toutefois, de tres-bonne heure, on pent distinguer une delicate 

 membrane autour de ce noyau, membrane qui s'ecarte de lui 

 graduellement, et qui preexiste, en consequence, a la plus 

 grande partie du contenu de la vesicule." It is difficult to 

 believe that the groups of nuclei, which are the first indications 

 of these structures, are really derived from the yellow cells. 

 Their mutual relations, if existing, can hardly have escaped 

 the notice of Perrier in the regenerating arm, or that of Wyville 

 Thomson in the Pentacrinoid larva. The first indication of the 

 sacculi noticed by the latter author^ in the early larva is a 

 minute vesicle containing a transparent fluid, which is imbedded 

 in the tissue at the base of each of the azygos tentacles ; but 

 if this had been anything like the yellow oil-cells, which are 

 abundant all over the Pentacrinoid, Thomson would surely 

 have noticed the fact. 



The above, however, are not my only reasons for hesitating 

 to accept this new doctrine of Vogt and Yung's respecting the 

 vegetable nature of the sacculi in Antedon rosacea. This 

 species is the only Crinoid in which I have found these struc- 

 tures in the interior of the body. Although they are very 

 abundant on the pinnules of Antedon Eschrichti and its 

 allied species, I have never found them anywhere else but at 

 the sides of the ambulacra. They are usually more numerous 

 on the arms than on the disc, but less so than on the pinnules, 

 where they alternate very regularly with the groups of ten- 

 tacles. Thus, for example, I can find none on the disc of an 

 Antedon microdiscus from Cape York, and very few at the 

 sides of the brachial ambulacra ; but they are extraordinarily 

 abundant on the pinnules. As a general rule, too, they are 

 more numerous on the outer pinnules than on those nearer 

 the disc, which are distended by the fertile portions of the 

 I ' Phil. Trans.; 1865, p. 527. 



