112 BULLETIN OF THE 



angular plates of the same character. Eadial shields small, minutely tuber- 

 culous, rounded triangular ; length to breadth 1.5 : .7 ; widely separated by 

 a group of half a dozen plates, of which the outer ones are much wider than 

 long. Two or three minute peg-like arm-spines situated in a notch low on 

 the side arm-plate. Color in alcohol, pale gray. 



Station 236, 420-470 fathom's, 1 specimen. Station 33, 300 fathoms, 

 (same species ?) 1 specimen. 



Ophiomusium archaster Wtv. Thom. MS. sp. nov. 



Plate n. Figs. 28, 89, 32. 



Special Marks. — Arms rather slender and tapering, cylindrical, or but 

 slightly wavy. Upper and under arm-plates persisting nearly to end of arm, 

 but no tentacles beyond third or fourth under plate. Genital opening bounded 

 by small close-set papillae. Disk covered by thick skin, its upper surface occu- 

 pied chiefly (and in half-grown specimens almost entirely) by rqdial shields 

 and large primary plates, with small scales between. Arms even and cylin- 

 drical. Four minute rudimentary arm-spines. 



Description of an Individual (Station 323). — Diameter of disk 10 mm. 

 Width of arm close to disk, without spines, 2.5 mm. Five mouth-papillae 

 on each side, short, pointed, closely joined, with one large, diamond-shaped, 

 at angle of jaw. Mouth-shields broad heart-shaped, with a peak within ; 

 length to breadth 1.3 : 1.5. Side mouth-shields long triangular, very broad 

 without ; tapering and curved inward, where they meet. First under arm- 

 plate very small, triangular, with angle inward ; the three next bear ten- 

 tacle-scales, and are three-sided, with lateral sides a little re-enteringly ciu-ved 

 and outer side slightly curved ; the rest are small, triangular, with outer 

 side curved. Side arm-plates thick, slightly swollen, somewhat constricted 

 within, meeting below throughout, and above beyond the third upper arm- 

 plate. First two upper arm-plates rounded and much wider than those 

 beyond, which are triangular, with an angle inward, lateral sides straight, 

 outer edge much curved. Disk flat, covered with thick, minutely tuberculous 

 pdates and scales. Radial shields sunken, of irregular rhomboidal shape, with 

 corners rounded ; length to breadth 1.7 : 1.3. Central primary plate smaller 

 than the others, circular, sunken, separated by a double row of small circular 

 scales from five large sunken, nearly round plates which surround it ; the rest 

 of the upper surface is covered with small rounded scales, with a larger one 

 on the margin. Under surface covered with small rounded plates, irregularly 

 disposed ; genital scales long and very narrow, on the free edge of which are 

 fine, short, stjuare papillae, corresponding to similar ones on the side ann-])lates. 

 One small rounded tentacle-scale, situated near inner angle of plate. Three 

 or four minute, slender, rounded arm-spines standing low down on arm- 

 plate ; upper one longest. Color in alcohol, straw. 



Station 323, 1900 fathoms, 5 specimens. 



