PART 5 A MONOGRAPH OF THE EXISTING CRINOIDS 501 



Zenometrinae) ; No. 16, p. 509 (in key; range); Unstalked crinoids of the Siboga-Exped., 1918, 

 p. 222 (in key; range), p. 232 (key to the included species). GISLEN, Zool. Bidrag Uppsala, 

 vol. 9, 1924, p. 212; Kungl. Fysiogr. Sallsk. Handl., new ser., vol. 45, No. 11, 1934, p. 18. 



Diagnosis. A genus of Zenometrinae in which the centrodorsal is elongate conical 

 with its surface divided into 5 radial areas by prominent interradial furrows; the 

 cirrus sockets are arranged in 2 columns in each radial area, the 2 columns being sepa- 

 rated by a midradial line or shallow groove; the cirri have rather numerous (27 to 40) 

 segments, of which the longest are about 4 times as long as broad or even longer, and 

 the last 10 are little if any longer than broad with the distal edge projecting dorsally; 

 the elements of the IBr series and the lower brachials are not in lateral contact, and 

 their edges are smooth; P ( and P a are absent. 



Type species. Antedon balanoides P. H. Carpenter, 1888. 



Geographical range.- Only known from the Philippine Islands. 



Bathymetrical range. From 142 to 150 meters. 



BALANOMETRA BALANOIDES (P. H. Carpenter) 



Antedon, sp. P. H. CARPENTER, Bull. Mus. Comp. Zool., vol. 9, No. 4, 1881, p. 155 (specimen from 

 near the Philippines lacking the lower pinnules). 



Antedon balanoides P. H. CARPENTER, Challenger Reports, Zoology, vol. 26, pt. 60, 1888, p. 207 (descrip- 

 tion; sta. 201), pi. 33, figs. 6, 7. A. H. CLARK, Smithsonian Misc. Coll., vol. 50, pt. 3, 1907, 

 p. 344 (related species exhibiting characters of the Basicurva group). HAM ANN, Bronn's Klassen 

 und Ordnungen des Tier-Reichs, vol. 2, Abt. 3, 1907, p. 1580. A. H. CLARK, Crinoids of the 

 Indian Ocean, 1912, p. 34 (of P. H. Carpenter, 1888= Balanometra balanoides). 



Perometra balanoides A. H. CLARK, Smithsonian Misc. Coll., vol. 50, pt. 3, 1907, p. 358 (listed); 

 vol. 52, pt. 2, 1908, p. 229 (compared with P. elongata). 



Perometra elongata A. H. CLARK, Smithsonian Misc. Coll., vol. 52, pt. 2, 1908, p. 229 (description; 

 Albatross sta. 5178). 



Balanometra balanoides A. H. CLARK, Crinoids of the Indian Ocean, 1912, p. 34 ( = Antedon balanoides 

 P. H. Carpenter, 1888), p. 238 (synonymy; locality); Smithsonian Misc. Coll., vol. 61, No. 15, 

 1913, p. 57 (published references to specimen in the B.M.; Challenger sta. 201); Unstalked crinoids 

 of the Si&opa-Exped., 1918, p. 232 (in key; range), p. 233 (references). GISLEN, Ark. Zool., 

 vol. 19, No. 32, 1928, p. 10, no. 49 (notes). 



Balanometra elongata A. H. CLARK, Crinoids of the Indian Ocean, 1912, p. 238 (synonymy; locality); 

 Unstalked crinoids of the Sj&oya-Exped., 1918, p. 232 (in key; range; references). 



Description of the type specimen. The centrodorsal is a much elongated cone 

 5.5 mm. high, its sides divided into 5 radial areas by deep interradial furrows, which 

 are broader than the cirrus sockets. In each radial area there is a shallower median 

 furrow not so broad as the cirrus sockets. The cirrus sockets in each radial area are 

 arranged in 2 columns of 6 or 7 each, beyond which more or less faint scars continue 

 the columns toward the dorsal pole. 



The cirri number about LX and have 35 to 40 segments of which the basal are short 

 and the following to the tenth or twelfth are much longer than broad and develop a faint 

 dorsal keel which projects beyond the base of the succeeding segments and decreases 

 in height proximally. The succeeding segments are shorter, though always longer 

 than broad, and become laterally compressed. 



The radials are concealed by the centrodorsal. The IBr, are oblong with a deeply 

 incised distal border, and are just in contact at their proximal angles. The IBr 2 

 (axillaries) are rhombic, their obtuse proximal angle rising to a synarthrial tubercle 

 with the median portion of the distal border of the IBr,. 



