242 



pelagic larvae, is quite without foundation, resting, no doubt, on misinter- 

 pretations and being due to most imperfect methods of research. (The 

 statement of the same author that these Ophiurids also are hermaphroditic 

 is equally phantastic, as I have shown in the paper quoted above). — As 

 for his statement that in Ophiothrix the larvae now develop into the typical 

 pluteus shape, now develop through a very imperfect larva, it rests on the 

 researches of Ap OS toll desi), who expressly says (Op. cit. p. 76) that the 

 nine tenths of the larvae reared by him did not develop into the true larval 

 shape but showed "une forme plus on moins arrondie, qui continue a 

 vivre, et dans laquelle nous avons suivi le developpement complet de 

 I'animal". Although he says to have "des raisons de pretendre que, jusqu'a 

 la fin du developpement de I'animal, il continuera a en etre ainsi" it is 

 evident that he has simply failed to rear the larvae beyond the stage with 

 the posterolateral arms, the larvae dying when they had reached this 

 stage — in fact, he states himself that "cette forme singuli^re ne continuera 

 plus a s'augmenter, mais peu a pen a se degrader, jusqu'au moment de 

 sa disparition." 



While thus we need not trouble with this imperfect larva with only two 

 arms, the direct statement ofApostolides that he has followed the com- 

 plete development of the still simpler embryos cannot simply be done 

 away with. It does, however, seem very hard to believe it to be correct 

 — and he does not give a single figure to accompany these remarkable 

 observations. That author moreover being anything but a first rate author- 

 ity it is impossible simply to endorse his statement. It is a fact that 

 Giard's statement of these Ophiurids as being at times of the year vivi- 

 parous, rests on misunderstood observations; it is therefore hardly too bold 

 to suggest that Apostolides' statement likewise may rest on misappre- 

 hension. In any case, we cannot accept the statement, until it has been 

 confirmed by renewed researches by a competent investigator. 



It would appear that Apostolides (Op. cit. p. 77) has also observed 

 those incomplete larval forms in the free, I would, however, suggest that 

 it may have been the rudimentary larval forms, Ophiopluteus Metschnikoffi 

 or 0. Claparedei, which he has observed. But that these larvae should also 

 belong to Ophiothrix, hke the typical Ophiopluteus, is exceedingly hard to 

 beUeve. The whole question, however, very much needs reinvestigation. 



As a further instance of poicilogony in Echinoderms Giard mentions 

 Asterina and Asterias. "Asterina cephea habitant les mers chaudes, aban- 

 donneau hasard dela vie pelagique des oeufs qui doivent donner naissance 

 a des larves nageuses ....A. gibbosa n'est done qu'une forme poeciloge- 



') N. Apostolides. Anatomie et developpement des Ophiurcs. Arch. Zool oxn^r & 

 g6n6r. X. 1881. " ' ^ 



