131 



and lias been reconslrucled in free hand in the figure. It is then quite 

 possible that the stonuu'h really fills the whole space between the skeletal 

 rods. Also the anterior vibralile band was indiscernible. The pigment- 

 ation is characteristic, consisting of fairly large |)ignient cells, scattered 

 along the body rods. 



Only one specimen of this very interesting larva was found, off Jolo, 

 20/III, \\)\ [. That it belongs to one of the Ophiothrichidae seems fairly 

 certain; in all probability it does, however, not belong to the genus Ophio- 

 tlui.v itself, but rather to one of the other genera within that family. 



Ophiopluteus of Ophiocoma. 



Ophiophileus Heiiseni Mrlsn. 



In a note on the 'Embryology of Ophiocoma echinata"') (".as\vell 

 Grave reports having reared the larva of this species, but gives no descript- 



l*'ig. 57. Larva of Ophiocoma echinala, ll'/j days old. .Mier a sketrli from life 

 by Caswell Grave, lOA'III. 1897. 



ion or figures of it. only the first embryonal stages being described. A full 

 report was never published. On my applying to Professor Grave concern- 

 ing this larva he most kindly sent me a sketch of the larva at the age 

 of 1 1 '/2 days for free disposal. Also slides containing some young larvae 

 were sent me. The sketch proved especially valuable, making it possible 

 to identify the Ophio(oma-la.r\'a with full certainty; it is reproduced in a 

 reduced scale in Fig. 57. I beg to express my deep gratitude to Professor 

 Grave for his kindness in supplying me with this important information. 

 In the said paper (irave mentions that the eggs "'after being fertilized 

 threw about themselves a tough prickly egg membrane", as is also shown 

 in figs. 1 2 of that ])aper. 1 would suggest that this peculiar membrane, 

 otherwise unknown in Ophiurids, is a special adaptation, serving as a 



') Johns Hopkins Univ. Circulars. Vol. l.s. 1898. p. (i- 



17" 



