190 



BULLETIN 75, UNITED STATES NATIONAL MUSEUM. 



This is still another well-characterized and easily recognized species, 

 of which the collection contains but a single specimen. The position 

 of tlie radial sliields, the shape of the upper arm plates, and the large 

 size of the first tentacle scales are noticeable features. 



OPIIIOMITRA ACONTOPHORA, new species.a 



Disk 3 mm. in diameter; arms about 20 mm. long. Disk covered 

 by numerous small scales, which are more or less concealed by the 

 many long, slender spear-like spines which they carry; these spines 

 are sharp pointed and have a few teeth near the tip. Radial shields 

 very long and narrow, closely joined for nearly or quite their entire 

 length. Upper arm plates small, triangular, with sides a little curved, 

 widely separated from each other. Interbrachial spaces below cov- 



FiG. 88. — Ophiomitra acontophora. X IC. a, from above; 6, from below; c, side view of three 



ARM JOINTS NEAR DISK. 



ered, like the disk, by numerous scales, and, except near the oral 

 shield, these carry the characteristic spines. Oral shields rounded 

 triangular, about as long as wide. Adoral plates large, wider without 

 than within where they meet. Oral papillae two or three on a side, 

 and one at apex of jaw, long, flat, and pointed. Genital slits rather 

 large. First under arm plate pentagonal, about as wide as long; 

 succeeding plates rather wider than long, pentagonal, with lateral 

 margins concave, separated from each other, except the first two or 

 three. Side arm plates large, meeting both above and below; each 

 plate carries four sharp, straight spines, of which the lowest is a little 

 the longest and slightly exceeds the joint. Tentacle scale single, of 

 moderate size. Color (dried from alcohol), nearly white. 



a "Akwv, signifying a javelin, and <f>opa, signifying cmrying, in referonco to the 

 numerous javelin-like spines borne on the disk. 



