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BULLETIN 75^ "UNITED STATES NATIONAL MUSEUM. 



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

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

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

 and bands on the arms grayish, the rest of the animal wliitish; 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 sldn; 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. — OpJuiologimus Jiexactis. 



Tliis genus may be defined as Opliioscolex with well-developed upper 

 arm plates, a definition used by layman for OpMotoma. OpMolo- 

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



Fig. 123.— Ophiologimus uexactis. X 10. o, from abo\t:; b, 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 sliields. 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- 



O'"04>:o and Xoycfioc, signifying worthy of mention, remarkable. 



b"E$, signifying six, and oktIc, signifying ray, in reference to the number of arms. 



