CLARK: BRITTLE-STARS. 315 



individual variant of 0. orstedii. It seems entitled to a name as a 

 well-marked variety for it is perfectly unmistakable in life and although 

 the color of the preserved specimen has become dingy, it could not be 

 confused with any other form. 



Ophiothrix lineata. 



LjTnan, 1860. Proc. Boston soc. nat. hist., 7, p. 201. 



This fine species is fairly common at the Tortugas, Florida, but 

 seems to occur only in Siphon ochalina and other sponges ; at least, none 

 were seen elsewhere. In all of its characters including coloration, it is 

 one of the least variable members of the genus and even growth-changes 

 are slight after the disk is two mm. across. The series taken at the 

 Tortugas ranges from 2 to 12 mm. in disk-diameter. It is interesting 

 to note that the largest specimen has not only the actually, but also 

 the relatively, longest arms; in the smallest specimen, the arms are 

 10-12 mm. long, or 5-6 times the disk-diameter while in the largest, 

 they are more than 120 mm. long or fully 10 times the disk-diameter. 



Ophiothrix pallida. 



Ljungman, 1871. Ofv. Kongl. vet.-akad. Forh., 28, p. 626. 



Koehler has given some excellent figures and a detailed description 

 (1913. Zool. jahrb. Suppl., 11, p. 377, pi. 20, fig. 5, pi. 21, fig. 10, 11) 

 of a type-specimen from the Stockholm Museum, of this rare species. 

 He refers to the specimen as "unique" but in this he is certainly mis- 

 taken as there is, in the M. C. Z. collection, a specimen received from 

 the Stockliolm Museum, collected in 180 fms. near Anguilla by Dr. 

 Goes, and hence unquestionably one of Ljungman's types. Indeed 

 from the fact that the disk is nearly 5 mm. across in the M. C. Z. 

 specimen, which is the measurement given by Ljungman, while the 

 Stockholm specimen is, Koehler says, only 3 mm. across, it might 

 be inferred that ours is the specimen on which the original descrip- 

 tion is based. The matter is not important, however, for the specimens 

 are alike in all particulars. Lyman was of the opinion that 0. pallida 

 was near 0. angtdata, while Koehler says it belongs to a different 

 "group," and he seems to consider it in the same "group" or section 

 as 0. suensonii. In this I decidedly agree with Lyman, as there is 

 no indication of a near relationship with 0. suensonii but on the 



