88 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



in his species any modifications of the ventral spines comparable to 

 those which are shown by H. L. Clark's specimen and especially by 

 mine which has exactly the same dimensions as the type of 0. scolo- 

 pendrica. However, it is certain that the two forms are very close, 

 and perhaps the study of a more complete series of individuals will 

 show intermediate forms which are now lacking. I may mention 

 also that the type of O. scolopendrica was found at a station (lat. 

 34° N., long. 138° E. ; 1,033 meters [565 fathoms] ) very close to that 

 where O. leucostictwrm was dredged (lat. 34° 09' N., long. 137° 55' E.; 

 927 meters [507 fathoms]). 



OPHIOTREMA TERTIUM, new species. 



Plate 21, figs. 2, 3, 7. 



Locality. — Albatross station 5349; Palawan Passage; Point 

 Tabonan bearing N. 85° E., 83.77 kilometers (45.2 miles) distant 

 (lat. 10° 54' 00" K, long. 118° 26' 20" E.) ; 1,335 meters (730 

 fathoms) ; December 27, 1908; co., S. 



One specimen (Cat. No. 41150, U.S.N.M.). 



Description. — The specimen is incomplete. Only one arm, about 

 65 mm. long, is preserved throughout its entire length. The disk is 

 pentagonal, but it is considerably deformed; it measures 15 mm. in 

 one diameter, but only 11 mm. in the other. 



The dorsal surface of the disk is also in a poor state of preserva- 

 tion; it is strongly wrinkled, and certain parts have been completely 

 torn away. It may be seen, however, that this surface is covered by 

 an integument bearing various kinds of structures; there are some- 

 what elongated and closely packed granules with a very rugose sur- 

 face ; among these granules there are flattened and somewhat lanceo- 

 late spines lying on the integument which bears them; these spines 

 are rather obtuse. The radial shields are almost completely hidden, 

 only their distal extremities being visible. The rugose granules of 

 the dorsal surface of the disk are continued onto the two or three 

 first arm segments and cover the upper arm plates as well as the side 

 arm plates. They are somewhat elongated on the arms, there be- 

 coming conical though remaining very rugose. 



The ventral surface of the disk has a covering similar to that of 

 the dorsal surface, but the spines occur only in the region near the 

 periphery, thence gradually disappearing so that two-thirds of the 

 ventral surface bears only granules which are very closely crowded, 

 and which persist to the mouth shields. The genital slits are large 

 and broad. 



The mouth shields are rather large, triangular, broader than long, 

 with the proximal angle sometimes a right angle and sometimes 

 obtuse, the later angles rounded, and the distal border gently con- 



