90 



BULLETIN 75, UNITED STATES NATIONAL MUSEUM. 



with outer margin convex; third, still larger, oblong, wider than long: 

 succeeding plates heptagonal, but quickly becoming pentagonal, in 

 contact up to eighth or ninth joint, after which they become small 

 and widely separated. Side arm plates large and somewhat swollen, 

 but not in contact either below or above on basal part of arm; each 

 plate carries three cylindrical spines, about one-third as long as plate 

 (or nearly one-half), and situated well back from margin; two lower 

 spines near together, while uppermost is near upper margin of plate. 

 Oral tentacle pores scarcely opening into mouth slit, protected by 

 five scales on each side; tentacle pores of arm protected by scales as 



follows, the number on 

 proximal side of pore 

 being given first: 4-5, 

 4-4, 4-3, 4-2, 3-2, and 

 2-1 ; of course the num- 

 ber on any particular 

 pore varies somewhat 

 on different arms, but 

 at least one distal scale 

 seems to continue even 

 to very tip of arm. 

 Color (dried from alco- 

 hol), ivory-white. 



Localities. Albatross 

 station 3749, off Suno 

 Saki, Japan, 83 to 158 

 fathoms, black sand, 

 shells, 1 specimen: sta- 

 tion 4892, Eastern Sea, 

 lat. 32 27' 30" N.; 

 long. 128 33' E., 181 

 fathoms, gray sand, 

 broken shells, rocks, 

 bottom temperature 50.2, 1 young specimen. Bathymetrical range, 

 83 to 181 fathoms. 



Type. Cat. No. 25604, U.S.N.M., from station 3749. 

 The specimen from station 4892 is only 4 mm. across the disk, and 

 both disk and arms are very flat. I at first supposed it to represent 

 a different species, but I am at last convinced it is simply the young 

 of pompliopliora . The figures given herewith (figs. 29 and 30) bring out 

 better than words can the differences in the scaling of disk and arms, 

 both above and below. As would naturally be expected in so young 

 a specimen, the scales are less swollen; the arm spines and comb 

 papillae are more pointed and the tentacle scales are much less numer- 

 ous. The species appears to be. very well characterized, for while it 



FIG. 30. OPHIURA POMPHOPHORA, YOUNG. X10. a, FROM ABOVE; 

 6, FROM BELOW; c, SIDE VIEW OF THREE ARM JOINTS NEAR DISK. 



