Narrative of Bahama Expedition. 131 



Lyman. This serpent-star, like many otherj, is extreme!}' 

 variable in coloration, the specimens from the Tortugas being 

 darker and less decidedly gray than those from the Bahamas. 

 In O. hcvis Lyman, the radial shields are evident in the 

 adults, but are covered in the younger specimens, the full 

 grown animals closely resembling O. cinerea. Another some- 

 what doubtful species is OpJiiiira appressa Say, which has the 

 radial shields and side mouth-shields covered, and nine arm- 

 spines. This species is considerably smaller than cincrca, and 

 some specimens are strikingly colored, the disk being pure 

 white marked with dark olive-green blotches. Another spec- 

 imen is considerablv larger, the mouth-shields are oblong 

 oval, the side mouth-shields are uncovered, and the radial 

 shields covered. One of the prettiest species secured at this 

 station was Ophiura nibiciinda Lyman, which has the disk 

 beautifully mottled with lake-red and grayish, the arms being 

 banded with the same colors. This seems to be the variety 

 mentioned b}' Lvman as •• a so-called variety of this species 

 which may be said to have the under side of O. cinerea, and 

 the upper side of O. nibiciuida.'"^ This statement almost ex- 

 actly expresses the facts in regard to our specimen. The 

 familiar Ophioconia cchinata Agass. is very abundant here, 

 and is the largest Ophiurian secured at the Tortugas. It is a 

 form admirably adapted to demonstrate the mouth-parts of the 

 serpent-star before classes. Ophioconia riisei Liitken is char- 

 acterized by having slender arm-spines, oval mouth-shields, 

 and a single tentacle-scale. It seems to grade into O. echinata 

 in many particulars. Ophioconia sp. is of a very light yellow- 

 ishjbrown, banded with darker brown in about equal propor- 

 tions, and is characterized by having one tentacle-scale, four 

 arm-spines, — the third and fourth the longest, — disk finely 

 and evenly granulated, and mouth-shields almost round. I- 

 am unable to place this specimen in any species described bv 

 Lyman. Ophioncrcis reticulata Liitken has the upper arm- 

 plates furnished with supplementary plates, and is of a yellow- 

 ish brown color reticulated with tine lines of reddish brown. 

 ^Illustrated Catalogue Mus. Comp. Zool. No. i, page 31. 



