332 RECENT OPHIURANS. 



Cuba: off Cape Cettz, 206 fms.; off Havana, 480 fms. Off St. Cruz, 

 D. W. I., 451-508 fms. Off Dominica, 333 fms. Off Martinique, 334- 

 476 fms. Off St. Lucia, 422 fms. Off St. Vincent, 464 fms. Off Barbados, 

 399 fms. All from the Blake collections. These specimens were labeled 0. ser- 

 ratum by Mr. Lyman and are recorded in his Blake report under that name, 

 but the differences pointed out above make a combination of characters which is 

 too constant and too important to ignore. I have found no specimens which are 

 intermediate between the two forms and have no doubt each is a valid, natural 

 species. 



1306. 0. MULTISPINUM H. L. Clark, 1911. Bull. 75 U. S. N. M., p. 133, f. 42. 



1 PARATYPE. Off Washington, 877 fms. 



1307. O. OLIGOPLACUM, sp. nov. {ohl-yos, few + irXaf, plate). Plate 20, f. 7, 8. 



Disk 5 mm. in diameter; arms more than 20 mm. long, very attenuate. 

 Similar to testudo in most particulars but differing in several important ones. 

 Chief of these is the arm-spines, which are six (five and then four distally) sharp, 

 short, subequal and well-spaced, instead of two or three peg-like ones crowded 

 near middle of side arm-plate. The disk-plates are very few (hence the name), 

 only 16 instead of 25^0 in testudo of about the same size. The radial shields 

 are closely joined for their entire length, instead of being separated proximally 

 by a large scale. The adoral plates are very large and the oral shields are rounded 

 pentagonal almost as wide as long instead of being almost triangular and much 

 longer than wide. As in testudo, there are only two pairs of tentacle-pores on 

 each arm and the upper and under arm-plates are confined to the basal joints. 

 Color (dry), nearly white. 



HoLOTYPE (M. C. Z. 526). Cuba: off Havana, 250-400 fms. Blake 

 Station 100. 



This specimen is labeled 0. testudo but no doubt Mr. Lyman failed to examine 

 it critically and so did not notice the characteristic arm-spines. Although the 

 near relationship to testudo need not be questioned, comparison with specimens 

 of that species having nearly the same disk diameter demonstrates beyond doubt 

 that oligoplacum is a perfectly distinct species. 



1808. O. PLANUM Lyman, 1878. Bull. M. C. Z., 5, p. 218, pi. 3, f. 46-48. 



6 specimens, including holotype and 1 paratype. Gulf of Mexico, 955 

 fms. Off coast of Portugal, (470 or) 1090 fms. Arabian Sea: off mouth of the 

 Indus, 1506 fms. 



