MUSEUM OF COMPARATIVE ZOOLOGY. 93 



much swollen platos, having deep furrows l)et\vecn them ; in centre a gioup 

 of six primary plates, separated by a row of irregular smaller plates ; outside 

 of these is another circle of ten equally large plates, of which the brachial 

 ones separate the inner ends of the radial shields. In each interbrachial space 

 there is also a large marginal plate. Radial shields longer than broad, outer 

 edge much wider than inner, joined without, but widely separated within by 

 a large rounded plate. Length to breadth 2 : 1. On the under surface the 

 plates are not so much swollen, and more regular ; in each interbrachial sjiace 

 are about three concentric rows, of from three to five plates each. Genital 

 plates long and rather wide, with outer end wider than inner ; along the free 

 edge is a close row of fine, even, tooth-like papillae, which become somewhat 

 longer and wider as they pass upward to form the arm-comb. Three arm- 

 spines short, blunt, and equally distant from each other. On first two sets of 

 pores four tentacle-scales on each side ; the third has three on each side ; the 

 fourth, one on the outside and three on the inside ; a little beyond the disk 

 there is only one on the inside. Color in alcohol, white. 

 Station IGS), 700 fathoms, 4 specimens. 



Ophioglypha ponderosa sp. nov. 



Plate II. Figs. 53 - 54. 



Special MarJcs. — Disk-plates high and excessively swollen. Upper arm- 

 plates rising in a high sharp ridge. Arm-spines minute, close-set, and like 

 little blocks. 



Description of an Individual (Station 232). — Diameter of disk 32 mm. 

 Width of arm at disk 6 mm. Mouth-papilla) square, fiat, crowded, forming a 

 continuous row with the scales of the mouth-tentacles, four or five on each side, 

 with three or four longer and pointed papilloo at angle of jaw. Mouth-shield 

 long and narrow, with outer end much rounded, lateral sides having a slightly 

 re-entering curve, and a short blunt angle within ; length to breadth 5.7 : 3. 

 Side mouth-shields long triangular, outer edges broader ; inner ends tapering, 

 where they meet. Under arm-plates broad hexagonal, with outer and inner 

 ends straight, and short angles on the sides ; the first plate is similar, but not 

 so large as the others ; farther out on the arm they become diamond-shaped. 

 Side arm-plates swollen, with outer edge curved, not meeting either above or 

 below. Upper arm-plates narrow, very highly arched, forming a sharp ridge ; 

 length to breadth about equal, wider without than within, four-sided, with 

 sides nearly straight. The ujiper surface of disk is covered by angular ])lat('s, 

 excessively swollen and lumpy, and compactly soldered ; the plates in centre 

 being smallest. Radial shields longer than wide, with edges irregularly curved, 

 meeting witliout, diverging inward, where they are separated by a large plate 

 of about the same size and shape ; in the interbrachial space, besides nujuerous 

 smaller plates, is one roughly triangular, with one angle inward ; on tlie lower 

 interbrachial sjiace the scales are not so nuich swollen ; there are about half a 



