MUSEUM OF COMPARATIVE ZOOLOGY. 245 



In looking over a large series, there may be found some difference in the 

 form of the radial shields, in the size and thickness of the fine central scales of 

 the disk, in the length and number of the arm-spines, which may be two or 

 three, and in the width of the arm. 



Constant features are the somewhat swollen and microscopically tuberculous 

 side arm-plates, the numerous and comparatively thin disk scales, and the 

 presence of only two under arm-plates furnished with tentacles. 



Station 100, off Morro Light, 250-400 fathoms. Station 132, Santa Cruz, 

 115 fathoms. Station 147, St. Kitts, 250 fathoms. Station 159, Guade- 

 loupe, 196 fathoms. Station 176, Dominica, 390 fathoms. Station 177, 

 Dominica, 118 fathoms. Station 185, Dominica, 333 fathoms. Station 208, 

 Martinique, 213 fathoms. Station 215, St. Lucia, 226 fathoms. Station 218, 

 St. Lucia, 164 fathoms. Station 231, St. Vincent, 95 fathoms. Station 

 238, Grenadines, 127 fathoms. Station 240, Grenadines, 164 fathoms. Sta- 

 tion 241, Grenadines, 163 fathoms. Station 248, Grenada, 161 fathoms. 

 Station 249, Grenada, 262 fathoms. Station 258, Grenada, 159 fathoms. 

 Station 262, Grenada, 92 fathoms. Station 263, Grenada, 159 fathoms. Sta- 

 tion 269, St. Vincent, 124 fathoms. Station 274, Barbados, 209 fathoms. 

 Station 280, Barbados, 221 fathoms. 



Ophiomusium Lymani Wtv. Thom. 



Plate V. Figs. 55-57. (Young.) 



The young, with a disk not larger than 5 mm., woidd be taken for a new 

 species. On the back is an elevated rosette of thick primary plates, each 

 having a central boss. Outside these lie the thick radial shields, and, in the 

 interbrachial spaces, two plates, the marginal one much the larger. Below, it 

 has, besides the genital scales, one large plate outside the mouth-shield, and 

 two or three very small ones on the margin. With a disk of 8 mm. it resem- 

 bles the adult of 0. validum, of the same size, except that the latter has larger 

 radial shields, fewer central scales, and, below, scarcely more than one great 

 plate outside the mouth-shield. 



Station 331, 35° 44' 40" N., 74° 40' 20" W., 898 fathoms. 



The following were adult : — 



Station 305, 41° 33' 15" N., 65° 51' 25" W., 810 fathoms. Station 307. 

 41° 29' 45" N., 65° 47' 10" W., 980 fathoms. Station 308. 41° 24' 45" N . 

 65° 35' 30" W., 1242 fathoms. Station 330, 31° 41' X., 74° 35' W., 1047 

 fathoms. Station 331, 35° 44' 40" N., 74° 40' 20" \V., B08 fathoms. Station 

 338, 38° 18' 40" N., 73° 18' 10" W., 922 fathoms. Station 339, 3>" 16' 4.V 

 N., 73° 10' 30" W., 1186 fathoms. Station 341, 39° 38' 20" N., 70° 56' W , 

 1241 fathoms. Station 342, 39° 43' N., 70° 55' 25" W., 1002 fathoms. 



