502 PROCEEDINGS OF THE NATIONAL MUSEUM, vol. xxxvi. 



the joints of the middle and distal pinnules are slightly " dicebox- 

 shaped," with a finely spinous surface and with the distal ends pro- 

 duced ventrally into two long sharp sj^ines, one on each side of the 

 perisome; this modification of the joints in the more proximal of the 

 pinnules affects only the distal portion, but later encroaches more and 

 more uj^on the proximal part, soon involving almost all of the joints. 



COMISSIA LUTKENI, new species. 



190S. Coniaster coirpingeri (part) A. H. Clark, Smiths. Miscell. Coll. (Quar- 

 terly Issue), LII, p. 202 (ten armed specimens). 



Centro-dorsal discoidal, the bare polar area broad and flat, 4 mm. 

 or 5 mm. in diameter; cirrus sockets arranged in two closely crowded 

 alternating rows. 



Cirri XV-XXV, 16-24 (usually 18-21) 7 mm. to 17 mm. long, 

 comparatively^ small and rather stout; first joint over twice as broad 

 as long, second and third nearly or quite as broad as long, fourth 

 half again to nearly twice as long as broad, a transition joint, usually 

 rather darker than the preceding, but light colored and with a pol- 

 ished surface in the distal fourth; following joints decreasing in 

 length, after the eighth being about twice as broad as long; occasion- 

 ally the fifth is a transition joint instead of the fourth, in which case 

 the two are about of the same size; fourth and following joints with 

 the dorsal and dorso-lateral distal edge everted and finely spinous; 

 this eversion of the distal edge of the joints gradually narrows ante- 

 riorly, on the last two or three joints becoming merely a single blunt 

 spine or tubercle; concurrently Avith its shortening, it gradually 

 attains a crescentic form, so that in lateral view the joints from the 

 fourth onward appear to be furnished with low dorsal spines which 

 arise gradually from the whole dorsal surface, at first terminal, 

 gradually becoming subterminal in position, and on the antepenul- 

 timate joint almost median ; opposing sj)ine median, arising from the 

 entire dorsal surface of the penultimate joint, short and blunt, reach- 

 ing not more than one-third the distal diameter of that joint in 

 height; terminal claw about as long as the penultimate joint, stout, 

 and moderately curved. 



Post-radial elements as given in the generic description; the arms 

 are 70 mm. to 75 mm. long. 



Pj 12 mm. to 15 mm. long, slightly stouter than the succeeding, 

 though not especially large, Avith about thirty-five joints, at first 

 about twice as broad as long, very gradually becoming longer and 

 about as long as broad after the twelfth or fifteenth; terminal comb 

 prominent, arising abruptly, with sixteen teeth, bluntly triangular, 

 nearly twice as long as broad at the base, basally in apposition, about 

 as high as the transverse diameter of the joints which bear them, 

 rather strongly recurved ; Pg similar, 10 mm. to 12 mm. long^ Pg 



