1;j2 Miscellaneous. 



smaller radius of the animal, is cylindrical and flexible, and its 

 surface is granular . In the larger individual there was nothing to 



& . M **l«*..*. -^ w^w *~* 



enable us to judge of its true nature ; but in the younger of the 

 two individuals of Caulaster that we have been able to examine, 

 other characters of more importance from the morphological point of 

 view are superadded to those above indicated. Thus at the base of 

 the dorsal appendage there are four large calcareous plates arranged 

 in a cross, and each bearing a small spine ; these plates are ar- 

 ranged nearly in the direction of the arms ; a fifth plate alternating 

 with two of them and opposite to the madreporic plate, evidently 

 forms part of the same cycle ; and five other smaller plates are 

 placed in the angles left free by the five plates of the first series. 

 We cannot help being struck with the absolute resemblance of these 

 ten alternating plates to those which form the periproct of the Sea- 

 Urchins, which Loven has compared to those forming the calico of 

 the Crinoids — an opinion that we shall have to discuss shortly. The 

 identity of arrangement of the dorsal plates of Caulaster with 

 those of the calice of the Crinoids is evident ; the presence in the 

 centre of the double cycle which they form of an appendage resem- 

 bling the peduncle which occupies the same place in the Crinoids 

 marks this resemblance still more strongly ; the homologies of the 

 latter parts are at once established ; and we thus find that, by means 

 of Caulaster , a close bond of union is established between the Cri- 

 noidea and the Stellerida. The character here indicated will appear 

 the more significant because in Lepty chaster, discovered during the 

 1 Challenger ' expedition, the young starfishes, which are developed 

 in a special pouch of their mother, are attached to the walls of this 

 pouch by the centre of their dorsal surface. On the other hand, the 

 rosette of plates which surrounds the dorsal appendage is an em- 

 bryonic character, since it disappears with age ; and this is pre- 

 cisely what ought to take place if we regard the Stellerida as a 

 form of Echinodermata derived from and higher than that of the 

 Crinoids. 



The young Asterire and Brisingce, as established by Loven and 

 myself, also present dorsal plates, arranged, at first, like those of the 

 calice of the Crinoidea ; we have demonstrated that, in Brisinga, 

 the plates of the first series become the odontophores ; these plates 

 cease to be visible externally in Caulaster. The question is whether 

 they really disappear in this animal, which would lead us to adopt 

 a new type of development among the Stellerida. Caulaster i> 

 evidently allied to the Ctenodtsci ; in the latter there exists a slight 

 tubercle, which seems to us to be homologous with the dorsal appendage 

 in Caulaster; and perhaps we might also compare with it a pro- 

 jecting knob which in Astropecten occupies the place where the 

 anus occurs in other starfishes. — Comptes Rendus, December 20, 

 1882, p. 1379. 



