80 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



Reports, Zoology, vol. 26, pt. 60, 1888, pp. 87, 89, 97. BATHER, in Lankester, A treatise on 

 zoology, pt. 3, Echinoderma, 1900, p. 195. A. H. CLAUK, Smithsonian Misc. Coll., vol. 50, 1907, 

 p. 348 (not available as a substitute for Zygometra}; Proc. U. S. Nat. Mus., vol. 34, 1908, p. 524 

 (type unidentifiable; not available as a substitute for Zygometra). 



Comatula (part) P. H. CARPENTER, Trans. Linn. Soc. (Zool.), ser. 2, vol. 2, 1879, p. 23, footnote. 



Hypomene WACHSMUTH AND SPRINGER, Proc. Acad. Nat. Sci. Philadelphia, 1881, p. 202 (p. 28 of 

 separate) . 



Antedon (part) BELL, Proc. Zool. Soc. London, 1882, p. 534, and following authors. 



Hyponeme ROLLESTON and JACKSON, Forms of animal life, 1888, p. 573. 



Zygometra A. H. CLARK, Smithsonian Misc. Coll., vol. 50, 1907, p. 339 (new species described as 

 Zygometra koehleri [= Catoptometra hartlaubi]) , pp. 345, 347 (diagnosis; genotype, Antedon 

 microdiscus Bell, 1884), Bull. Mus. Comp. Zool., vol. 51, 1908, p. 246 (characters; genotype); 

 Proc. Biol. Soc. Washington, vol. 21, 1908, p. 134 (closely related to Eudiocrinus, restricted; 

 arm structure), p. 135 (assigned to the family Zygometridae) ; Proc. U. S. Nat. Mus., vol. 34, 

 1908, p. 211 (referred to the Zygometridae), p. 212 (occurs in Japan [refers to Catoptometra] ), 

 p. 271 (relation to Eudiocrinus), p. 276 (referred to the Zygometridae), p. 542 (listed); vol. 35, 

 1908, p. 118, fig. 15 (arm structure); Proc. Biol. Soc. Washington, vol. 22, 1909, p. 2 (cirri and 

 lower pinnules comparable to those of Thalassometridae), p. 174; Die Fauna Sudwest-Austra- 

 liens, vol. 3, Lief. 13, 1911, p. 439 (3 peculiar Australian species); Mem. Australian Mus., vol. 

 4, 1911, p. 715 (recent species first described in 1882; fossil representatives), p. 724 (Australian 

 species), p. 732 (in key), p. 734 (key to Australian species), p. 760 (reference; characters; range); 

 Rec. Indian Mus., vol. 7, pt. 3, 1912, p. 267 (new species discovered related to Z. comata but 

 occurring farther west) ; Smithsonian Misc. Coll., vol. 60, No. 10, 1912, p. 1 (Hyponome sarsi the 

 detached visceral mass of some species of this genus); Crinoids of the Indian Ocean, 1912, p. 

 9 (occurs in shallow water in a very limited area; also in the European Jura; possesses additional 

 species in Australia), p. 10 (does not extend north of Hongkong; absent from Japan; reason), 

 p. 11 (occurs in Mergui Archipelago), p. 21 (range; this closely parallels that of Comatula Solaris 

 and C. peclinata), p. 56 (in key), p. 103 (synonymy; type); Die Fauna Siidwest-Australiens, vol. 

 4, Lief. 6, 1913, p. 311 (discussion of the small species and comparison with those of Heteromelra, 

 and of the large species and comparison with those of Himeromelra) ; Journ. Washington Acad. 

 Sci., vol. 5, 1915, p. 8 (very highly developed in the Australian fauna). F. W. CLARKE and 

 WHEELER, U. S. Geol. Surv. Prof. Pap. 90-L, 1915, p. 195 (inorganic constituents of the skeleton) ; 

 Prof. Pap. 102, 1917, pp. 23 ff. (same). A. H. CLARK, Unstalked crinoids of the Si6o(?o-Exped., 

 1918, p. 59 (key to the included species). F. W. CLARKE and WHEELER, U. S. Geol. Surv. 

 Prof. Pap. 124, 1922, p. 20 (analysis of skeleton). GISLEN, Zool. Bidrag Uppsala, vol. 9, 1924, 

 p. 35 (brachial homologies), p. 84 (distal intersyzygial interval); Kungl. Fysiogr. Sallsk. 

 Handl., new ser., vol. 45, No. 11, 1934, p. 18. 



Diagnosis. A genus of Zygometridae in which the outer cirrus segments are much 

 shorter than the earlier and bear prominent dorsal spines. 



Geographical range. From Hongkong and the Philippine Islands southward to 

 Sandon Bluffs, New South Wales, and to between Fremantle and Geraldton, Western 

 Australia, and westward to Ceylon. 



Bathymetrical range. From the shore line down to 128 (?135) meters. The 

 species are especially inhabitants of the sublittoral zone. 



Remarks. of the six species included in this genus four are closely allied, while 

 the other two are rather widely different from these and from each other. When 

 typically developed, Zygometra elegans is easily distinguished from Z. microdiscus, but 

 some specimens seem to be more or less intermediate, so that the former has been 

 considered as simply a form of the latter. The relation between Zygometra elegans 

 and Z. comata is essentially the same as that between Z. microdiscus and Z. elegans. 

 In most cases Z. comata is readily distinguishable from Z. elegans, but specimens may 



