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TWO NKW CKIXOIDS 



By AUSTIN H. CLARK 



Curator. Dknsion nf Echinodcrms. U.S. Xational Mit.setim 



(With Two Plates) 



The collection of criiioids hrouglu hack by the |()hll^()ll-SlllilhsoIliaIl 

 Deep-Sea Expedition from the cruise of 1933 was a notable one, 

 including 143 specimens representin^S^ Tf) species, of which 2 are tmde- 

 scribed. one of these representing a genus which heretofore was 

 known only from the Indian and Pacific Oceans. These two new 

 species are herein described. 



PSATHYROMETRA ACUTA, n. sp. 



Plate I. figs. I, 2; plate 2. fig. 4 



Locality. — Caroline station 102; northeast of Puerto Rico (lat. 

 i8°5i'N., long. 64°32'W.); 90 to 500 fathoms; March 4, 1933. 

 Three specimens ( I'.S.N.M. nos. £.3121 [type], E.3122, and E.3123). 



Description. — The centrodorsal (])1. i, figs, i, 2) is sharply conical, 

 the sides in profile straight in the ])roxinial two thirds, thence very 

 gradually and slightly turning outward and running to the pointed 

 tip, longer than broad, 2.7 mm wide at the base and 3.5 mm long, 

 measured along- the sides interradially. The cirrus sockets are closely 

 crowded all around the centrodorsal, which shows no trace of division 

 into radial areas. There are proximally three columns of cirrus 

 sockets in each radial area; the two outer columns of cirrus s(jckets 

 consist of usually nine sockets, which diminish gradually in size from 

 the base to the tip. The median column is incom])lete. consisting of 

 three or four sockets onlv and ending slightly beyond the middle of 

 the centrodorsal. 



The cirri are lacking. 



The ends of the basal rays are indicated by low, broad, and incon- 

 s]:)icuous tubercles in the interradial angles of the calyx. 



Smithsonian Miscellaneous Collections, Vol. 91. No. 4 



