386 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



KEY TO THE SPECIES OF THE GENUS CALOMETRA 



a 1 . Larger, the arms 90-100 mm. long; usually 42-50 cirrus segments; ossicles of the division series 

 with everted edges and brachials with everted distal ends giving the animal a very rough appear- 

 ance (Kei Islands to the Moluccas; 239-439 meters) discoidea (p. 386) 



a*. Smaller, the arms 55-70 mm. long; not over 40 cirrus segments; edges of the ossicles of the divi- 

 sion series and ends of the brachials little if at all everted so that the animal appears smooth 

 (southern Japan; 100-195 [7254] meters) callista (p. 390) 



CALOMETRA DISCOIDEA (P. H. Carpenter) 

 [See vol. 1, pt. 2, fig. 311 (proximal pinnules), p. 223.] 



Antedon discoidea P. H. CARPENTER, Challenger Reports, Zoology, vol. 26, part 60, 1888, p. 134 (de- 

 scription; Challenger station 192), pi. 10, figs. 1, 2. HAMANN, Bronns Klassen und Ordnungen 

 des Tier-Reichs, vol. 2, Abt. 3, 1907, p. 1578 (listed). A. H. CLARK, Crinoids of the Indian 

 Ocean, 1912, p. 33 (of P. H. Carpenter, lS88=Gephyromelra discoidea). 



Calomelra discoidea A. H. CLARK, Smithsonian Misc. Coll., vol. 50, pt. 3, 1907, p. 363 (listed) ; Proc. 

 U. S. Nat. Mus., vol. 39, 1911, p. 545 (Albatross station 5577); Zool. Anz. vol. 39, 1912, No. 

 11/12, p. 422 (cirri compared with those of C. diana); Crinoids of the Indian Ocean, 1912, 

 p. 179 (synonymy; localities); Smithsonian Misc. Coll., vol. 61, No. 15, 1913, p. 42 (published 

 references to specimens in the B. M.; Challenger station 192; characters). GISLN, Zool. Bidrag 

 Uppsala, vol. 9, 1924, p. 90 (synarthrial tubercles). A. H. CLARK, Journ. Linn. Soc. (Zool.), 

 vol. 36, No. 249, 1929, p. 646 (Rotti Strait; 100 fathoms). 



Gephyrometra discoidea A. H. CLARK, Crinoids of the Indian Ocean, 1912, p. 33 (editorial error). 



Diagnostic features. This species is larger than C. callista, the arms being from 

 90 mm. to 100 mm. in length; the ossicles of the division series have everted edges 

 and the brachials have everted distal ends so that the animal has a very rough ap- 

 pearance; there are usually 42-50 cirrus segments. 



Description of the larger specimen from Albatross station 5617 (No. 85475). The 

 centrodorsal is discoidal with a broad smooth slightly concave dorsal pole 3 mm. in 

 diameter. The cirrus sockets are arranged in 2 crowded more or less regularly alter- 

 nating marginal rows. 



The cirri are XXII, 38-47 (usually 42-45), from 25 mm. to 30 mm. long. The 

 first 4 segments are short, about twice as broad as long, the fifth is about one third 

 broader than long, and the sixth-tenth are from slightly longer than to half again 

 as long as the proximal width with the ventral and dorsal profiles forming a slight 

 angle with each other and both almost imperceptibly concave so that both the dorsal 

 and ventral ends of the segments are slightly projecting. After the tenth the length 

 of the segments rather rapidly decreases so that the segments in the distal third of 

 the cirri are very short, about twice as broad as long. In these short distal segments 

 the cirri taper very slightly to the tip. On about the twelfth a slight longitudinally 

 elongate tubercle with a sharply rounded crest appears at the distal end of the seg- 

 ments on the dorsal side which in the short distal segments develops into a high 

 broad dorsal spine the base of which involves the whole dorsal surface of the segment 

 in the median line while the proximal border is strongly convex and the distal straight 

 or slightly concave and about at right angles to the longitudinal axis of the cirri. 

 The crests and the points of these spines are slightly blunted. The opposing spine 

 arises from the entire dorsal surface of the penultimate segment which, as a result 

 of the distal taper of the cirri, is very small. It is triangular with the distal border 

 forming a straight line with the distal edge of the penultimate segment and the 



