THE OPHIURID^. 



181 



Color in alcohol : gray. 



\ m 



L 



One specimen from Station 3406; 551 f. 



This species shows some resemblance to Ophiothmmms remotus Lym.j from 

 which it is, however, very easily distinguished. It is on account of that 

 resemblance that we have placed it in the genus OjMothamnus , which seems 

 to be as ill defined as OjMomitra. Lyma?^ thinks he has found characters of 

 generic value in the internal structure (the genital plates) ; we are not 

 convinced that he is right in this. He gives figures of the internal skeleton 

 usually only of one species of each genus, but evidently that is too little to 

 determine which characters are of generic^ and which only of specific value. 



58. Ophiothrix spiculata Lcconte. 



Lyman: Challeuger Opliiuroidea, p. 226. 



Of this species there are six specimens from Panama. 



59. Ophiothrix galapagensis n. sp 



Plate XX. Figs. 1-4, 



Diameter of disk, 5 mm.; width of arm close to disk, without spines, 

 1 mm. ; length of arms about 5 to 6 times the diameter of the disk. The 

 vertical oval has 17-18 conical tooth papillae; 5-6 in the median line, 

 arran^^ed in a single row, and 6 in each marginal row; the latter are a little 

 longer than the median ones; the lower ones are very small, growing grad- 

 ually longer upwards. 3-4 flat teeth with straight cutting edge ; the upper 

 one is the narrowest. Mouth shield twice as broad as long, with a peak 

 within and without; corners rounded, inner and outer sides concave. Side 

 mouth shields equally broad in their whole length, meeting within. 



First ventral plate rather large, rounded ; those beyond broadly in 

 contact, inner angle thus truncated ; outer edge curved on the second and 

 third, farther out feebly concave. Inner and outer laterals slightly concave, 

 outer corners truncated. The second ventral plate is longer than broad ; 

 those beyond rapidly grow broader, and just outside tlie disk they are 

 broader than long, and they remain so almost to the end of the arm. Side 

 arm-plates with rather prominent spine-ridge ; there is a naked space 

 separating those of each two adjoining joints. Dorsal plates rather broadly 

 in contact, inner angle truncated; outer edge much rounded, lateral sides 



* 



12 



/■ 



^ 



