556 PROCEEDINOS OF THE NATIONAL MUSEUM. tol. 39. 



The most striking characteristic of this species is its slenderness, 

 especially the slenderness of the cirri, the long proximal segments of 

 which are twice as long as broad. 



PACHYLOMETRA LUNA, new species. 



Centrodorsal as in P. investigatoris, but proportionately shorter; 

 the cirrus sockets are arranged in ten columns of two or three each. 



Cirri XXV, 23-25, 30 mm. to 40 mm. long, stout, resembling those 

 of P. investigatoris. 



Division series and arm bases essentially as in P. investigatoris; 

 but the basal rays are much larger, rhombic, entirely concealing 

 the radials in the interradial angles of the calyx; the division series 

 and arm bases make a slightly greater angle with the dorso-ventral 

 axis than in P. investigatoris, though in general the shape and pro- 

 portions are the same; the division series are more convex dorsally 

 than those of P. investigatoris, and the center of each in the median 

 dorsal line rises into a broadly rounded tubercle instead of being 

 obscurely carinate, as in P. investigatoris; similarly, indistinct broad 

 tubercles occur on the oblong proximal brachials; the interradial 

 angles are slightly more deeply excavated than are those of P. inves- 

 tigatoris. All the IIBr series are 4 (3 + 4) and all the IIIBr series 

 are 2 (1 + 2), all but a single one of the latter being developed inter- 

 nally. 



The twenty-nine arms of the type are 150 mm. long. 



Type.— C&t. No. 27503, U.S.N.M., from station 5325. 



PACHYLOMETRA SELENE, new species. 



This new species is most closely related to P. investigatoris and 

 P. luna. 



Centrodorsal resembling that of P. investigatoris. 



Cirri XXX, 17-19, 25 mm. to 30 mm. long, much shorter and with 

 fewer segments than those of the two species mentioned; the seg- 

 ments in the outer half have rather strongly produced distal dorsal 

 edges, which bear a rounded tubercle in the median line, so that 

 the dorsal profile of the cirri is strongly serrate. 



The division series and arm bases diverge, as in P. investigatoris, 

 and are only slightly convex dorsally, not so much so even as in that 

 species; each ossicle is smooth and even dorsally, but beai-s in its 

 center a very prominent high rounded tubercle; these tubercles gradu- 

 ally become obsolete after the proximal quarter of the arms, but 

 may be traced as far as the beginning of the distal half; two of the 

 IIBr series are 4 (3 + 4) and two 2; there are no IIIBr series present. 



The fourteen arms are 205 mm. long. 



Type.— Cat. No. 27504, U.S.N.M., from station 5523. 



Another specimen was taken at this station which has twenty ' 

 arms 195 mm. long; nine IIBr 4 (3 + 4) and one IIBr 2 series are i 



