222 



of the larva. The crossed pedicellaria?, present in both larval stages, de- 

 finitely prove that it belongs to the suborder of the Forcipulata, and rea- 

 sons are given for the suggestion that it is the larva of a deep-sea form. 

 It is a noticeable fact that no traces of a vibratile band are found. 



Through the kindness of Professor Jules Richard 1 have received 

 from the Musee Oceanographique of Monaco some specimens of this very 

 interesting larva. The examination of these specimens has led me to an 

 interpretation differing rather considerably from that given by Koehler 

 & Vaney. Both the stages described are far advanced metamorphosis 

 stages, so that the true shape of the larva is not to be made out, the larval 

 body most probably ( as may be inferred from a comparison with the 

 later metamorphosis-stages of Asterias ) already being for the greater 

 part absorbed. But this much is still clear, that the larva belongs to the 

 Brachiolaria-type. In fact, there can be no doubt that what Koehler & 

 Vaney take to be the mouth of the larva is really the sucking disk of the 

 Brachiolaria, round which are found the three typical Brachiolarian arms. 

 They are of quite typical shape, ca. 2 5 mm long, cylindrical, the point 

 being covered with small papillae; furthermore there is a close series of 

 similar small papillae from the base of the median, anterior Brachiolarian 

 arm backwards to each side of the sucking disk. On the larval body there 

 are besides found the last vestiges of the other larval arms, mostly reduced 

 to mere papilliform processes, which can no longer be identified with 

 certainty, excepting only the unpaired, median dorsal process, situated 

 behind the median Brachiolarian arm. The larva is in a stage correspond- 

 ing very closely with that represented in PI. 21, Fig. 13 of (iemmiU's 

 Memoir on the development of Asterias rubens 1 ). If only the body and 

 arms were a little more contracted - as they would certainly be on a 

 not very careful preservation - we would here have a figure very well 

 representing the Stellosph&ra. If we now look upon the figures on PI. 

 XXIV of Koehler' s work, it is evident that the figure 10 represents a 

 larva seen from the apical pole, showing the sucking disk in the middle, 

 with the three Brachiolarian arms (very poorly represented - they have 

 evidently been unusually contracted in that specimen; the papillae on the 

 point of these "pedicelles peribuccaux" were also observed by Koehler 

 & Vaney). The smaller papillae scattered over the body are the remnants 

 of the larval arms, not at all the beginning tubefeet of the young starfish, 

 as would seem to be the opinion of the authors. The six large calcareous 

 plates with the clusters of spines are the terminal plates of the starfish. 

 Another curious result of this examination is that the I. stage of Koehler 

 & Vaney is really the older, more advanced stage, their II. stage being 



') Phil. Trans. Ser. B. Vol. 205. 1914. 



