252 BULLETIN 'IS, UNITED STATES NATIONAL MUSEUM. 



imens before me. He calls the arm spines "blunt," while they seem 

 to me to be unusually sharp. He says the "color in alcohol" is 

 "pale brown;" all the specimens before me have the radial shields 

 and bands on the arms grayish, the rest of the animal whitish; the 

 degree of contrast varies much in different specimens, but is usually 

 very slight. 



OPHIOLOGIMUS, new genus/* 



Disk covered by a fine coat of scales, more or less concealed by 

 thin skin; both skin and scales extend out on base of arms. No visi- 

 ble radial shields. Upper and under arm plates well developed. Ten- 

 tacle scales present. Oral papillae numerous, but arm spines few. 



Type-species . OpJiiologimus Jiexactis . 



This genus may be defined as OpJiioscolex with well-developed upper 

 arm plates, a definition used by Lyman for OpTiiotoma. Ophiolo- 

 gimus differs from OpJiiotoma very markedly, however, not only in 



FIG. 123. OPHIOLOGIMUS HEXACTIS. X 10. c, FROM ABOVE; 6, FROM BELOW; c, SIDE VIEW OF THREE 



ARM JOINTS NEAR DISK. 



disk covering but especially in the presence of well-developed tentacle 

 scales. 



OPHIOLOGIMUS HEXACTIS, new species.6 



Disk 5 mm. in diameter; arms, six, about 20 mm. long. Disk 

 covered by a close coat of fine scales, more or less concealed by skin. 

 No visible radial shields. Bases of arms covered like disk. Upper 

 arm plates thin but well developed, rhombic with distal angle rounded, 

 longer than wide, more or less overlapping. Interbrachial spaces 

 below covered by skin, which contains, peripherally, scattered scales. 

 Genital slits rather small. Oral shields rounded triangular, wider 

 than long. Adoral plates large, three times as long as wide, meeting 

 broadly within and separating oral shield from first under arm plate 

 without; oral plates indistinct. Oral papillae numerous, very small, 

 thin and truncate; outer ones largest. First under arm plate pen- 



a "0(f)o and Ao^o^, signifying worthy of mention, remarkable. 



b"E, signifying six, and d/cr^-, signifying ray, in reference to the number of arms. 



