316 bulletin: museltvi of comparatr'e zoology. 



contrary, were it not for the colored stripe on the upper side of the arm 

 I should be at a loss to distinguish 0. pallida from 0. angulata; in 

 the spinulation of the disk, in the form of the upper and under arm- 

 plates and in the arm-spines, the type-specimen of 0. pallida before 

 me can be almost exactly matched from our large series of 0. angulata. 



Ophiothkex axgulata var. atrolineata, var. nov. 

 ater = black -|- lineatus = with lines, in reference to the marking of the arms. 



Plate 5, fig. 3. 



Holotype. — M. C. Z., 4,154. British West Indies: Tobago, Buccoo 

 Bay, April, 1916. Carnegie Expedition. H. L. Clark coll. 



Although the specimen on which I base this variety is very young 

 (disk, 3 mm., arms, 12-15 mm.), the coloration is so distinctive it 

 seems worthy of a name. The upper surface of disk and arms is 

 lavendar, with the arm- spines of practically the same tint; orally 

 the specimen is whitish. On the upper side of each arm is a broad, 

 longitudinal, very black line, which does not extend on to the disk. 



The conspicuous line on the arm suggests that this specimen might 

 be a hybrid between 0. angulata and 0. suensonii, but there is nothing 

 else in the structure to indicate such an origin. As the dorsal stripe 

 on the arm in 0. angulata is usually white, the present specimen 

 represents an extraordinary variety. 



Ophiotheix angulata ^•ar. megal^spis, var. nov. 

 jjiiyas (jxtyaX) = big + dairls = shield, in reference to the large radial shields. 



Plate 8, fig. 3. 



Holotijpe.— M. C. Z., 4,223. Gulf of Mexico: off northeastern 

 Yucatan, 51 fms. Blake Station (1880) XXX. J. R. Bartlett 

 coll. 



Disk 7 mm. in diameter; arms 30-35 mm. long. Disk covered 

 by a coat of relatively coarse but not very distinct scales, most of 

 which bear short, slender, thorny spinelets; a few bear bifid or trifid 

 stumps and a few are naked. Radial shields large, triangular, 2.3 

 mm. long by 1.3 mm. viide, in contact only at distal tip but only very 

 slightly separated elsewhere; each shield is very smooth and sharply 



