198 BULLETIN 15, UNITED STATES NATIONAL MUSEUM. 



across the disk, but most of them are much less than that and some 

 may be the young of other species. The extensive bathymetrical and 

 temperature ranges would indicate the presence of more than one 

 species in the lot, but such small specimens of Ophiacantha can seldom 

 be positively identified. 



OPHIACANTHA LEVISPINA. 



Ophiacantha levispina LYMAN, Bull. Mus. Comp. Zool., vol. 5, 1878, p. 147. 



Localities. Albatross station 490S, Eastern Sea, lat. 31 40' N. ; 

 long. 129 29' 40" E., 434 fathoms, gray globigerina ooze, bottom 

 temperature 42.9, 7 specimens; station 4912, Eastern Sea, lat. 31 

 39' 40" N.; long. 129 20' E., 391 fathoms, gray globigerina ooze, 

 bottom temperature 41.9, 1 specimen; station 4915, Eastern Sea, 

 lat, 31 31' N.; long. 129 25' 30" E., 427 fathoms, gray globigerina 

 ooze, broken shells, bottom temperature 41.9, 2 specimens; station 

 4916, Eastern Sea, lat. 30 25' N. ; long. 129 6' 40" E., 361 fathoms, 

 gray sand, globigerina, broken shells, bottom temperature 42.7, 11 

 specimens; station 4917, Eastern Sea, lat. 30 24' N. ; long. 129 6' E., 

 361 fathoms, gray sand, globigerina, broken shells, bottom tempera- 

 ture 42.7, 8 specimens; station 4918, Eastern Sea, lat. 30 22' N.; 

 long. 129 8' 30" E., 361 fathoms, gray sand, globigerina, broken 

 shells, bottom temperature 42.7, 11 specimens; station 4919, East- 

 ern Sea, lat. 30 34' N.; long. 129 19' 30" E., 440 fathoms, globig- 

 erina ooze, bottom temperature 41.8, 19 specimens; station 4956, 

 off southern Japan, lat. 32 32' N. ; long. 132 25' E., 720 fathoms, 

 green-brown mud, fine gray sand, foraminifera, bottom temperature 

 37.5, 7 specimens; station 4971, off eastern Japan, lat. 33 23' 30" 

 N. ; long. 135 34' E., 649 fathoms, green-brown mud, foraminifera, 

 bottom temperature, 38.1, 1 specimen; station 4980, off eastern 

 Japan, lat. 34 9' N. ; long. 137 55' E., 507 fathoms, brown mud, 

 fine sand, foraminifera, bottom temperature 39, 4 specimens; station 

 4984, Sea of Japan, lat. 43 4' 20" N.; long. 140 12' 10" E., 224 to 

 248 fathoms, green mud, bottom temperature 33, 1 specimen; sta- 

 tion 5083, off Omai Saki Light, lat. 34 4' 20" N. ; long. 137 57' 30" 

 E., 624 fathoms, fine gray sand, globigerina, bottom temperature 

 38.1, 2 specimens. Bathymetrical range, 224 to 720 fathoms. Tem- 

 perature range, 42.9 to 33. Seventy-four specimens. 



Lyman considered his single specimen, which measured 6 mm. 

 across the disk, as immature, but the largest specimen before me is 

 only 9 mm. in disk diameter and the great majority are under 7 mm. 

 The broad distal oral papilla is the most striking mark of this species 

 and is fortunately very constant. It serves to distinguish levispina 

 from pentagona at once, although in other characters the two species 

 often approach each other very nearly. There is considerable diver- 

 sity shown in the shape of the arm plates and oral shields; the latter 



