150 



.htpaii represiMils aiiothci- species llian lluil liom Cape, bul llie dilTerences 

 are loo insignilicaiit lor inakiiii^ il necessary lo desi^nale it as a separate 

 species at preseiil. In any case liie two lornis must be very closely 

 related. 



Another, younger specimen, from the same locality and the same day, 

 ])rohably also belongs to this species, although it difTers in the antero- 

 lateral arms being longer than the postoral ones and in the suboral cavity 

 being indislincl. In this specimen the posterolateral arms have the same 



outward direction as 

 in the type. 



The suggestion made 

 in the work quoted 

 that this larva may 

 belong to some Am- 

 phiiira-species is with- 

 out real support. It 

 was made on account 

 of the similarity be- 

 tween this larva and 

 Ophiopliileiis birnacu- 



latus (Joh. Mull.), 

 which latter was re- 

 ferred to the genus 

 Amphiura on account 

 of the fact that the 

 young Ophiurid, as 



Fig. 77. Skeleton of Ophiopliiteiis similis. -»%. 

 Letters as in fig. 61. 



^^ 



-X_ 



3v 



Fig. 78. Fart of posterolalcral rod of Ophiopluteus similis. 



iyii; 



shown in the figures of .loh. Miiller (V. Abhandl. Taf. V, Fig. 6) has 

 two papillae on each mouth angle, a feature mainly characteristic of Am- 

 phiura. However, as I have shown recently^) that Ophiopluteus mancus is 

 the larva of Amphiura fdiformis, the suggestion that O. binuiculatus might 

 belong to an Amphiura becomes improbable. The two papilla> of the young 

 Ophiurid are hardly tlie typical infradental papillai of the Amphiurid type, 

 but more probably tooth papillae situated in the inner part of the mouth; 

 in Amphiura filiformis 1 have found the infradental papillae to appear 

 only at a much later stage of development. The fact of the occurrence 

 of this larval type both at Cape and .Japan is not of sufficient zoogeo- 

 graphical importance for indicating to which species of Ophiurids it belongs. 

 Whether it is more nearly related to Ophiupluleus biniaculalus must also 

 remain uncertain for the present. 



■) On the development and the larval forms of some Scandinavian Echinoderms. p. 138. 



