OPHIUKANS OF UNITED STATES NATIONAL MUSEUM. 83 



trace of these special papillae which should form a bunch or a double row so as to 

 build for the mouth pore that particular covering indicated by Verrill. 



I can not, therefore, give to my specimens the name of Ophiectodia pectinula 

 and I retain for them the name of Ophiacantha echinulata. Besides, there can be 

 no objection to that species being classified in the subgenus Ophioscalus of Verrill. 



Thus 0. echinulata remains well characterized by the peculiar covering of the 

 upper face of the disk, which may hide, more or less completely, the radial shields, 

 and the latter offer, in their shape and size, the variations indicated by Lyman. 

 The species is also featured by the tentacular scale of the brachial pores, which is 

 extremely long, narrow, very much pointed and rough, and almost as long as the 

 corresponding under brachial plate ; often, but not always, there are two scales on 

 the first tentacular brachial pore ; the under bracliial plates, which are elongated, 

 narrow, with a convex distal side, have also a rather characteristic shape. 



Apart from the arrangement of the oral papillae, the description given by Verrill 

 of 0. pectinula may, therefore, apply to the specimens which I have studied ; but, 

 on the other hand, I can not separate them from 0. echinulata, for it is understood 

 that as regards the shape of the radial shields such a restriction must be made as 

 Lyman himself made in 1883. This being so, must Ophiectodia, pectinula be con- 

 sidered as a synonym of OpTiiacantha echinulata^ Although this synonymy be 

 very enticing, I do not think it ought to be admitted now, since Verrill has definitely 

 taken the characters of the oral papillae as a basis for the separation of the two species. 

 The question will not be settled except by comparing a great many specimens; 

 especially a revision of the specimens gathered by the Blake and indicated by Lyman 

 in 1883 would be particularly interesting and is most desirable. 



OPHIACANTHA ENOPLA Lyman. 



Fish Hawk station 1124. Aug. 26; 1882. Lat. 40 01' N.; long. 68 54' W.; 

 640 fathoms; fne. s., gn. m., limestone nodules; temp. 39 F. One specimen. 



OPHIACANTHA FRATERNA Verrill. 



Plate 11, figs. 5-6. 

 See for bibliography: 



Ophiacaniha fraterna VEEEILL (85), p. 545. 

 Ophiacanthafraterna VEBBILL (99a), pp. 321, 324. 



Albatross station 2105. Nov. 6, 1883. Lat. 37 50' N.; long. 73 03' 50" W.; 

 1,395 fathoms; glob, oz.; temp. 41 F. Nine specimens. 



Albatross station 2678. May 6, 1886. Lat. 32 40' N.; long. 76 40' 30" W.; 

 731 fathoms; It. gy. oz.; temp. 38.7 F. Three specimens. 



In the larger specimens the diameter of the disk ranges between 8 and 9.5 mm.; 

 in the smallest it does not exceed 3 mm. The largest examples are not in a very 

 good state ; the brachial spines are very incomplete, and the arms themselves are 

 broken at a small distance from their base. In an example with a disk of 8 mm., 

 the arms are from 40 to 45 mm. long. 



I have been able to make sure of my determination by comparing these speci- 

 mens with a specimen determined by Verrill and lent me by theU. S. National Museum, 



