NORTH PACIFIC OPHIURANS IN NATIONAL MUSEUM CLARK. 55 



and at various stations in the Sea of Japan, from lat. 35 54' N.; 

 and long. 129 46' E., northward to Saghalin Island (lat. 48 32' 

 45" N.; long. 145 7' 30" E.). Between Saghalin and the western 

 end of the Aleutians no specimens of this ophiuran were taken, 

 though it is hard to explain their absence in that region ; perhaps we 

 may assume that depth, temperature, and bottom were not suitably 

 combined at any of the thirty-two stations of the Albatross. Off the 

 American coast the bathymetrical range of this species is extraordi- 

 nary, extending, as stated above, from 67 fathoms to 1,771, while the 

 bottom temperature varied from 48.5 down to 34.9. In the Sea of 

 Japan, however, the bathymetrical range is only from 172 to 429 

 fathoms, with a very low bottom temperature, 33.9-32.4; off the 

 east coast of Saghalin specimens were taken in only 73 fathoms, but 

 the bottom temperature was extraordinarily low, 30.9, while off 

 eastern Japan they were taken in water as warm as 49.4 and again 

 in water as deep as 507 fathoms. 



It is remarkable that, among previously known species, one of the 

 nearest allies of leptoctenia appears to be a species taken by the 

 Challenger off the coast of Brazil and called by Lyman OpMoglypha 

 ljungmani. Judging only by the figures of the upper side, it is almost 

 impossible to distinguish the two species; orally, however, there are 

 some obvious and important differences in the shape of the oral 

 shields and the first under arm plate, as well as in the oral papillae 

 and tentacle scales. When the specimens themselves are compared, 

 the much longer arms and thicker disk of ljungmani distinguish the 

 two species at a glance. It is interesting to note (what Lyman does 

 not mention) that in some specimens of ljungmani the disk scales 

 carry scattered minute spinelets exactly like those which occur in 

 leptoctenia. From kinbergi, which it resembles somewhat in its 

 slender comb papillae, leptoctenia is distinguished by the difference in 

 the disk scaling, the absence of pits between the basal under arm 

 plates, and the absence of a rounded tentacle scale on the arm pores. 

 From young individuals of sarsii or luikeni, with which it is most 

 likely to be confused, the sharp, slender comb papillae will invariably 

 distinguish it. 



OPHIURA QUADRISPINA, new species.a 



Disk 9 mm. in diameter; arms about 30 mm. long. Disk rather 

 flat, nearly circular, covered by two or three hundred scales, among 

 which the six primary plates are more or less distinguishable though 

 they are very rarely conspicuous. Radial shields of moderate size, 

 rather longer than broad, separated or touching distally. Upper 

 arm plates more or less tetragonal, at first wider than long and 



o-Quattuor (quadri-), signifying four, smdspinus, signifying spine, in reference to the 

 four arm spines. 



