634 PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. [1885. 



smoother than the remaiuing brachials, as often happens in this spe- 

 cies ; they are also darker in color. The free arms above the first brach- 

 ials appear much more delicate and are of a lighter color. Th6 lower 

 7 or 8 brachials on each arm are much flattened, dorsally and laterally, 

 the edges aloDg which these surfaces meet being more or less sharply an- 

 gular and produced to form narrow wing-like extensions reaching nearly 

 the entire length of the joint, or short, stout, more or less spiniform pro- 

 jections most developed at the upper ends of the joints and directed up- 

 ward and outward. The one is but a modification of the other, all grada- 

 tions occurring from the elongate process to the simple spine, the former 

 often breaking up into two or even three spines, the lower of which are 

 much the smaller and generally quite minute. One of the most com- 

 mon conditions is a slightly raised subangular or rounded edge, be- 

 ginning just above the lower end of the joint and continuing without 

 much, if any, increase in size to near the upper end, where it becomes 

 abruptly enlarged, the spine-like process thus formed being some- 

 times acutely, at others obtusely, j>oiuted, and often squarely cut off 

 above. Where the raised edge is not continuous, it is generally repre- 

 sented by the one or two smaller spines above mentioned. 



In addition to the lateral processes, there is on most of the arms a 

 median series of spines, of about the same length as the lateral ones; 

 but more sjnne-like in shape, and acutely or bluntly pointed, though 

 occasionally transversely expanded at the tip. They are located at the 

 extreme upper end of the joints, slightly overlapping the next above, 

 are directed upward and outward, and may begin anywhere from the 

 5th to the 12th brachial. They extend over from 2 to 13 joints, being 

 generally largest below and gradually decreasing in size upward, be- 

 coming at the same time more acute and more appressed. Above the 

 flattened brachials the joints become normal. All the joints below the 

 free arms are much more flattened than usual, and some of the palmars 

 and distichals are more or /less produced at the sides. 



In specimen B the ray and arm joints are all less flattened than in 

 A, and the lateral edges less continuously produced, generally bearing 

 only from 1 to 3 spines, which are smaller and more acute. The me- 

 dian series of spines is more constant, and reaches farther up on the arms, 

 and there are often two, three, or even more spines along the upper edge 

 of each joint, not always regularly arranged, and generally limited to 

 one side or the other. The spines of this series are frequently very 

 broad, thin and square at the upper end. 



KECORD OF SPECIMENS. 



Off Havaua, Cuba: 



Stations 2156-2169, 78 to 278 fathoms, Cr., 1884, 16 specimens (12357). 

 Stations 2319-2350, 67 to 279 fathoms, Cr., 1885, 75 specimens (12358). 

 South of Cuba : 



Latitude 19° 56' 06" N., longitude 75° 47' 32" W., 254 fathoms; station 2134, 

 1884, 1 specimen (12547). 



