68 BULLETIN 75, UNITED STATES NATIONAL MUSEUM. 



First under arm plate hexagonal, large, much wider than long; next 

 two about as long as wide, somewhat pentagonal; succeeding ones 

 rounded pentagonal or oblong, very much wider than long; all but 

 first three or four well separated from each other. Side arm plates 

 somewhat swollen, nearly or quite in contact both above and below 

 from base to tip of arm; each plate carries six, or often seven, short, 

 peg-like arm spines, middle ones usually longest, though not notice- 

 ably longer than lowest; none is half as long as a joint. Oral tentacle 

 pores rather large, opening into mouth slit, with four or five scales 

 on each side. Tentacle pores of arm confined to first four or five 

 joints, but a single, minute tentacle scale extends far out on arm, 

 lying close against lowest arm spine. There are several tentacle 

 scales on each of the basal pores, but they can be distinguished only 

 with difficulty from the little arm spines. Color (dried from alcohol), 

 nearly white, though with more or less of a yellow tinge. 



FIG. 18. OPHIURA CALYPTOLKPIS. X4. a, FROM ABOVE; b, FROM BELOW; c, SIDE VIEW OF TWO ARM 



JOINTS NEAR DISK. 



Localities. Albatross station 3698, off Manazuru Zaki, Honshu, 

 Japan, 153 fathoms, green mud, volcanic ashes, sand, 2 specimens; 

 station 5088, Sagami Bay, lat. 35 11' 25" N.; long. 139 28' 20" E., 

 369 to 405 fathoms, green mud, bottom temperature 41.8, 1 speci- 

 men; station 5091, Uraga Strait, lat. 35 4' 10" N.; long. 139 38' 

 12" E., 197 fathoms, green mud, coarse black sand, pebbles, bottom 

 temperature, 47.8, 21 specimens; station 5092, Uraga Strait, lat. 

 35 4' 50" N.; long. 139 38' 18" E., 70 fathoms, coarse black sand, 

 bottom temperature 56.3, 1 specimen. Bathymetrical range, 70 to 

 405 fathoms. Temperature range, 56.3 to 41.8. Twenty-five 

 specimens. 



Type. Cat. No. 25635, U.S.N.M., from station 3698. 



There can be no doubt that this species is closely allied to 0. albata 

 Lyman, which was collected by the Challenger near Japan. I have 

 not seen that species, but the description and figures of the upper 

 arm plates are entirely different from what calyptolepis shows, and 

 moreover no reference is made to any concealment of the disk scales 

 by a granular skin in albata. It has therefore seemed best to me to 

 keep the two species separate, at least for the present. 



