0PIII0CX1DA PUTNAM I. H 



standing out independently, as pad-like ridges (a generic character), 

 which are stout and swelled ; upper arm-plates represented by a double 

 row of irregular elongated warts, which just at the base of the arm are 

 increased in number, so as to form a clump of different-sized pieces. 

 At the tapering end of the arm there are still the two warts at the 

 base of each joint, and between these a double row of fine grains. 

 Disk wholly covered above by the ten great radial shields, which are 

 regular, slightly swelled, and smooth ; at the insertion of the arm and 

 in the interbrachial space they form a slight notch or re-entering angle. 

 Interbrachial spaces below covered with thick skin, without spines or 

 scales ; genital-slits with a large prominent scale at their outer end, 

 whose edge can be seen from above. Arm-spines like little stumps, 

 thorny at their ends ; towards the end of the arm they become more 

 flattened, and the three lowest ones are armed with three or four flat- 

 tened hooks. The first joint outside the mouth-shield has two or three 

 spines on each side ; the second three, and the rest four. Color, in 

 alcohol: upper surface lined and marl >led with dark green and light 

 yellow, interbrachial spaces below dark green ; under surface light 

 greenish. 



Another specimen had a disk of 5.5 mm ', and amis of 18 mm -. The 

 mouth-shields were all regular, excejit the madreporic, which was 

 swelled. The back of the disk had a central pentagon of marbled 

 bluish and yellow, surrounded by a band of yellowish. The animal 

 doubtless has the power of moving the side arm-plates, which in this 

 specimen were folded close on the arm. 



Locality unknown, but supposed to have been brought from the 

 Pacific by the Exploring Expedition. 



Ophiocnida Putnami* Sp. nov. 



Plate I., fig. 9. 



Special Marks. — Nine or ten flat arm-spines, the upper ones with 

 broad ends ; they closely cover the arm, as if with grains of rice reg- 

 ularly set in rows. Disk beset with similar, but smaller spines. Two 

 swelled papilla? at the apex of the mouth-angle. Two tentacle-scales. 



Description of the Specimen. — Diameter of disk, 16 mn \ Width of arm, 

 2.5"""'; length of arm about 72 mm . From outer side of mouth-shield to 

 outer corner of opposite mouth-slit, 4.S' 1 ""- ; distance from outer corner 



* Xanied after the late Captain W. II. A. Putnam, a man of a line taste in natural history, and 

 who enriched this Museum with remarkable collections made during his sea voyages. 



