500 BULLETIN 82, UNITED STATES NATIONAL MUSEUM VOLUME 1 



half. The distal edge is very concave, and is everted and coarsely spiny. The 

 IBi^ are shorter than the radials, being about three tunes as broad as their length 

 in the midline. The proximal edge is concave, the distal fairly deeply incised by the 

 axillary. The IBrj are not in apposition. The axillaries are slightly broader than 

 long; all the edges are concave, the distal more so than the proximal. 



The first three sy/ygies are at brachials 3+4, 9 + 10, and 14 + 15. The fragments 

 which remain of the more distal parts of the arms show syzygial pairs separated by 

 one brachial. The width at the first syzygy is 0.7 mm. 



The middle part of the dorsal surfaces of the division series and the proximal 

 brachials as far as the second syzygy is beset with low and irregular spines; in addi- 

 tion the distal edges of the brachials between the first and second syzygies are everted 

 and produced into spines. Beyond the second syzygy the brachials have smooth and 

 somewhat hollow dorsal surfaces, but their distal edges are more everted and produced 

 into stronger spines than those of the lower brachials. 



Pj is of 4 to 6 unequal segments, and very short, but of different lengths on different 

 arms ; on some arms it is much less, on others more, than 1 mm. long. On one arm the 

 first segment is short, the second longer and much wider than any of the remainder, 

 but twice as long as broad; the third and fourth are slightly longer than broad; the 

 fifth short and small. The PI of another arm is of equal length, and the proportions 

 of the segments are the same except that the second segment is not conspicuously 

 wider than the others. In a very short P! of four segments, each segment is only 

 slightly longer than broad. 



P 2 is generally similar to PI. It is of five or six segments, of which all but the first 

 and last may be considerably longer than broad; the second may be more massive 

 than the others. P 2 may be of the same length as, or longer or shorter than, the P, 

 of the same arm. P. is similar. 



The geoital pinnules, of which P 3 is the first, are more than twice as long as the 

 oral pinnules. P 3 is 2.5 mm. long and of nine segments, of which all but the first 

 two are elongated, being up to five times as long as broad. The distal ends of the 

 segments are everted and spiny. An enormous gonad lies along the third to sixth 

 segments of one, a still larger one along the third to seventh segments of another. 

 They are testes. P 4 , P e and P 4 are similar to P 3 . They lack ambulacral grooves. 

 It cannot be stated whether the genitals extend beyond P 4 , for none is complete beyond. 



The disk is naked. 



Locality. B.A.N.Z.A.K.E. station 107; off MacRobertson Land, Antarctica (lat. 

 6645' S., long. 6203' E.); 219 meters; February 16, 1931 [John, 1939] (1, B.M.). 



Genus BALANOMETRA A. H. Clark 



Antedon (part) P. H. CARPENTER, Bull. Mus. Corop. Zool., vol. 9, No. 4, 1881, p. 155, and following 

 authors. 



Perometra (part) A. H. CLARK, Smithsonian Misc. Coll., vol. 50, pt. 3, 1907, p. 258. 



Balanomelra A. H. CLARK, Proc. Biol. Soc. Washington, vol. 22, 1909, p. 177 (diagnosis; type species 

 Antedon balanoides P. H. Carpenter, 1888; referred to the Zenometrinae) ; Crinoids of the Indian 

 Ocean, 1912, p. 10 (absent from Japan), p. 11 (absent from the west coast of the Malay peninsula, 

 the Andamans, and further westward), p. 26 (confined to the Philippine Islands), p. 61 (in key) 

 p. 238 (original reference; type); Die Crinolden der Antarktis, 1915, p. 114 (in key to the genera 

 of Zenometrinae); Journ. Washington Acad. Sci., vol. 7, 1917, No. 5, p. 127 (referred to the 



