Nariiativi-: of Baiia:ma Expedition. 131 



Lyman. This serpent-star, like many other.";, is extremely 

 variable in coloration, the specimens from the Tortugas beini^ 

 darker and less decidedly gray than those from the Bahamas. 

 In O. /icz'is L\'man. the radial shields are evident in the 

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

 grown animals closely resembling O. cincvca. Another some- 

 what doubtful species is Ophiiira appressa Say, which has the 

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

 spines. This species is considerably smaller than riiicrea. and 

 some specimens are strikingly colored, the disk being pure 

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

 imen is considerabl}' 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 Ophitira nihicuiida 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 variet\- 

 mentioned by Lyman 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. rubiciijida.'''^ This statement almost ex- 

 actly expresses the facts in regard to our specimen. The 

 familiar Ophiocoiiui cchiiiata Agass. is very abundant here, 

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

 form admirably adapted to demonstrate the mouth-p^rts of the 

 serpent-star before classes. Ophiocoma nisei Liitken is char- 

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

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

 in many particulars. Op/iioconia sp. is of a very light \ellow- 

 ish brown, banded with darker brown in about equal propor- 

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

 arm-spines, — the third and fovn-lh the longest, — disk lineh' 

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

 am unable to place this specimen in an\- species described b\- 

 Lyman. Opiiioncrcis rcticnlata Liitken has the upper arm- 

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

 ish brown color reticulated with line lines of reddish brown, 



illluslrated Catalogue Miis. Coinp. Zool. No. i, page 31. 



