446 bulletin: museum of comparative zoology. 



15-20 mm. across. There is some diversity in the scahng of the disk, 

 in the size of the radial shields and in the basal under arm-plates, 

 but the differences are relatively unimportant. 



Station 3684. Eastern Tropical Pacific, 50' N., 137° 45' W., 

 2463 fms. Bott. temp.? Gy. yl. glob. oz. 



Station 4647. Eastern Tropical Pacific, 4° 33' S., 87° 42' 30" Wi, 

 2005 fms. Bott. temp. 35.4°. Lt. gy. and br. glob. oz. 



Station 4649. Eastern Tropical Pacific, 5° 17' S., 85° 20' W., 

 2235 fms. Bott. temp. 35.4°. Fne. stky. gy. m. 



Station 4651. West of Aguja Point, Peru, 111 miles. 2222 fms. 

 Bott. temp. 35.4°. Fne. stky. gy. m. 



Station 4658. West of Peru, 8° 30' S., 85° 36' W., 2370 fms. 

 Bott. temp. 35.3°. Fne. gn. m., mang. nod. 



Station 4670. W^est of Palominos Light House, Peru, 105 miles. 

 3209 fms. Bott. temp., 35.4°. Fne. dk. br. m. 



Station 4672. Southwest of Palominos Light House, Peru, 88 

 miles. 2845 fms. Bott. temp. 35.2°. Fne. dk. br. infus. m. 



Station 4742. Eastern Tropical Pacific, 4' S., 117° 7' W., 2320 fms. 

 Bott. temp. 34.3°. Fne. It. gy. glob. oz. 



Bathymetrical range, 2005-3209 fms. Extremes of temperature, 

 35.4°-34.3°. 



Forty-eight specimens. 



Ophiura stenobrachia,'^ sp. nov. 

 Plate 5, fig. I, 2. 



Disk 9 mm. in diameter; arms all Ijroken but it seems improbable 

 that they exceeded 18-20 mm.; they are very slender only 1.3 mm. 

 in diameter at base. Disk covered by about 150-200 plates among 

 which the primaries can scarcely be distinguished; the disk is highly 

 arched, its thickness at center being nearly 3 mm.; the margin of 

 each interradial area is nearly or quite fully occupied by a single 

 large plate, little of which, however, is visible from above. Radial 

 shields moderately large, roughly triangular, nearly or quite as wide 

 as long, in contact at outer ends but well separated within. x\rm- 

 comb small, not extending well up on to the upper surface of the arm, 

 composed of few, flat, blunt, close-set papillae, of which the upper- 

 most are largest. Upper arm-plates triangular, exceedingly small, 

 about as long as wide, separated (except on the first two basal seg- 



1 ar&'os = narrow + [:) paxl<j^v = arm, in reference to the very slender arms. 



