OPHIURANS OF UNITED STATES NATIONAL MUSEUM. 25 



Fish Hawk station 7512. Mar. 25, 1903. 3$ miles SE. by E. of Fowey Rocks 

 Light; 170 fathoms; sft.; temp. 51 F. Two specimens. 



Fish Hawk station 7513. Mar. 25, 1903. Gulf Stream off Cape Florida, 6J 

 miles E. S. E. E. of Fowey Rocks Light; 200 fathoms; gy. m.; temp. 46 F. 

 One specimen. 



The largest specimens are those from station 2376 in which the diameter of 

 the disk ranges between 15 and 17.5 mm.; the arms, in the largest specimen, reach 

 52 mm. In the others, the diameter of the disk ranges from 9 to 1 1 mm. 



In these examples, I find variations which are analogous to those formerly 

 indicated by Lyman and Verrill, some of the specimens recalling in certain of 

 their characters, Lyman's description, while the others are more in accordance with 

 Verrill's; in all of them, the spines invariably number two. Verrill thought that the 

 differences observed by him in the specimens gathered by the "Bahama Expedition" 

 were due to the size of the specimens, the diameter of the disk in Lyman's type 

 being 9 mm., while in Verrill's material, this diameter reached 12 mm. But, 

 according to what I have observed, those differences are due not alone to size. 

 Lyman, moreover, reported in 1883 certain variations in the specimens from the 

 Blake, and, besides other things, he noted that the brachial spines might amount 

 to three; the diameter of the disk in the largest specimen which he had observed 

 was 15 mm. 



The specimens from station 7512 are chiefly in accordance with Lyman's descrip- 

 tion. The upper brachial plates show, from the base of the arms, the shape of loz- 

 enges and remain very small; the radial shields are large, triangular, widely sepa- 

 rated; but the mouth shields are longer than indicated by Lyman and their shape 

 is the same as that figured by Verrill. 



The specimen from station 2401, although being very near the foregoing ones 

 as far as the size is concerned, differs from them in various respects. The whole 

 body is covered with a yellowish tegument which more or less completely hides 

 the underlying plates. The upper face of the disk with its large triangular radial 

 shields, recalls Lyman's type, but the upper brachial plates are of a different shape. 

 The first one or two of these plates are very short, rectangular, and much wider 

 than long; the third one, also rectangular, is almost as wide as long, with a broad 

 and convex distal side, and a narrower proximal side. The following plates get 

 more elongated, but up to the tenth or twelfth one, they preserve their proximal 

 side distinct, and they do not until afterwards become triangular or lozenge-shaped. 

 The under brachial plates offer nothing particular, but the mouth shields are 

 shorter than on the preceding samples and they recall the shape drawn by Lyman. 

 The bracbial spines are extremely short. 



The four samples from station 2376 have also their bodies covered with a 

 fairly thick and opaque tegument which hides the outline of the plates. The 

 upper face of the disk recalls the arrangements represented by Verrill, with rather 

 small radial shields which are oval and rather widely separated. The first two 

 upper brachial plates are very short, wider than long and of little importance. The 

 third one, quadrangular, is much wider than long; the fourth is trapezoidal, with a 

 proximal side narrower than the distal side, and it is still a little wider than long. 



