338 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



and a second specimen of the type species was described under the heading Homalo- 

 metra denticulata, 



HOMALOMETRA DENTICULATA (P. H. Carpenter) 

 PLATE 37, FIGURES 166, 167 



Antedon denticulata P. H. CARPENTER, Challenger Reports, Zoology, vol. 26, pt. 60, 1888, p. 130 

 (description; Challenger station 190), pi. 22, figs. 1, 2. BELL, Ann. Mag. Nat. Hist., ser. 6, 

 vol. 2, 1888, p. 403 (comparison with A. wilsoni [Ptilometra macronema, young]). HARTLAUB, 

 Bull. Mus. Comp. Zool., vol. 27, 1895, p. 130 (systematic and bathymetrical relationships). 

 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 (identity). 



Nanometra denticulata A. H. CLARK, Smithsonian Misc. Coll., vol. 50, 1907, p. 349 (listed). 



Amphimetra denticulata A. H. CLARK, Die Fauna Siidwest-Australiens, vol. 3, Lief. 13, 1911, p. 441 

 (Australian tropical species; Arafura Sea); Crinoids of the Indian Ocean, 1912, p. 33 (identity), 

 p. 113 (synonymy; habitat; notes on the type specimen); Smithsonian Misc. Coll., vol. 61, 

 No. 15, 1913, p. 25 (published reference to the specimen in the B. M.; Challenger station 190). 



Homalometra denticulata A. H. CLARK, Unstalked crinoids of the Sibogra-Exped., 1918, p. 91 (refer- 

 ences; detailed description; station 167), p. 273 (listed), pi. 5 (colored figure), pi. 27, figs. 101, 

 102. GISLEN, Arkiv for Zoologi, vol. 19, No. 32, 1928, p. 5, No. 18 (notes). 



Description. The centrodorsal is very thin, discoidal, with a broad, very slightly 

 convex, dorsal pole 1.5 mm. in diameter, which bears numerous very small scattered 

 tubercles, among which, about the border, are larger irregular flattened tubercles, 

 frequently surrounded by a circle of the smaller ones, apparently indicating the loca- 

 tion of obsolete cirrus sockets. The cirrus sockets are arranged in a single slightly 

 irregular marginal row. 



The cirri are XIII, 27-29, from 25 to 27 mm. long, very slender, gradually and 

 slowly tapering to a point, only slightly and irregularly curved. The first segment 

 is very short, the second is about twice as broad as long, the third is from about as 

 long as broad to half again as long as broad, and the fourth and fifth and following are 

 about four times as long as broad, becoming slightly shorter (from two and one- 

 half to three times as long as broad) toward the end of the second third of the cirri, 

 and longer again terminally. The longer cirrus segments are very slightly constricted 

 centrally; those in the outer third of the cirri have the ventral and dorsal profiles 

 more nearly straight. The terminal claw is very long and very slender, about as 

 long as the preceding segment, with the tip more or less curved downward. 



The edges of the radials are bordered by a row of small rounded beadlike tubercles, 

 and there are smaller and less conspicuous tubercles scattered over their surface in 

 the interradial angles. The IBr t are very short, more than four times as broad as 

 long. The IBr 2 (axillaries) are low triangular, twice as broad as long. The IIBr 

 series are 4(3+4). The ossicles of the division series and first two brachials have 

 slight lateral extensions and are sharply flattened laterally as far as the base of P t . 



The 11 arms are 90 mm. long. The first brachial is very short, about four tunes 

 as broad as long, only slightly wedge-shaped. The second is irregularly quadrate, 

 about three times as broad as the median length. The first syzygial pair (composed 

 of brachials 3 + 4) is remarkable for its extreme shortness, being about three times 

 as broad as long, slightly longer inwardly than outwardly, the hypozygal oblong, the 

 epizygal wedge-shaped. The next four brachials are nearly oblong, with the distal 

 border produced. The following brachials are remarkably uniform, slightly wedge- 



