S| BULLETIN 82, I SITED STATES NATIONAL MUSEUM 



393 (discussion; localities*; Crinoids of the Indian Ocean, 1912, pp. 31, 33, 39 (identity); p. 103 

 my; summary of previous records ; Die Fauna Sudwest-Australiens, vol. 4, Lief. 6, 

 1018, p. 810 South Passage, Shark Hay, 9 m.; description); Smithsonian Misc. Coll., vol. 61, 

 No. 1"), 1018, p. 20 (published references to specimens in British Museum; localities; characters 

 ,.f the specimens).- i: bbobb, Abh. Senck. Naturf. Gcs., vol. 35, Heft 1, 1913, p. 82 



-i [elands), p. 00 Am Islands, west of Ngaiguli, 14 m.; characters of the 2 specimens). — 

 \ II Clabk, Etec. Western Australian Mus., vol. 1, pt. 3, 1914, p. 123 (detailed comparison 

 with Z. elegans; specimens from northwest Australia and from Lewis Island positively identified 

 as this species); Internal. Rev. gesamt. Hydrobiol. und Hydrogr., 1915, p. 224 ff. (detailed 

 account of distribution in Australia). — F. W. Clarke and Wheeler, U. S. Geol. Surv. Prof. 

 Tap 00 1 , 1915, p. 191 (inorganic constituents of skeleton). — H. L. Clark, Biol. Results Fish- 

 ing Exper. I". I. S. h'.mleavouT, 1909-14, vol. 4, pt. 1, 1916, p. 19 (new locality; notes). — Hart- 

 meter, Mitt. zool. Mus. Berlin, vol. 8, Heft 2, 1910, p. 234 (W-Australien, Nos. 5966, 6136; 

 Mermaidatrasse, No. 5607). — F. W. Clarke and Wheeler, U. S. Geol. Surv. Prof. Pap. 102, 

 1917, p. 21 (Aru Islands; inorganic constituents of skeleton). — A. H. Clark, Unstalked crinoids 

 of the Si'&oya-Exped., 1918, p. 59 (in key; range), p. 60 (synonymy; notes; station 273), p. 275 

 (listed), pp. 277, 278 (inorganic constituent* of skeleton).- — Gislen, Kungl. Svenska Vet. 

 Akad. Handl., vol. 59, No. 4, 1919, p. 3 (listed), p. 5 (station 13), pp. 19, 22, 23.— A. H. Clark, 

 Smithsonian' Misc. Coll., vol. 72, No. 7, 1921, p. 22 (food).— F. W. Clarke and Wheeler, 

 T'. S. Geol. Surv. Prof. Pap. 124, 1922, p. 17 (inorganic constituents of skeleton).— Gislen, 

 Zool. Bidrag Uppsala, vol. 9, 1924, p. 278 (Broome, Western Australia; shore; food), figs. 142, 

 1 13, p. 95 (pinnule articulations). — A. H. Clark, Journ. Linn. Soc. (Zool.), vol. 36, 1929, p. 637 

 (Baudin Island, 8-15 fathoms^.- — Gislen, Kungl. Fysiogr. Sallsk. Handl., new ser., vol. 45, No. 

 11, 1934, pp. 36, 37, 40.— H. L. Clark, Mem. Mus. Comp. Zool., vol. 55, 1938, p. 32 (Roebuck 

 Bay; Broome; Lagrange Bay, 5-8 fathoms; notes). 



Zygomctra multiradiata A. H. Clark, Smithsonian Misc. Coll., vol. 50, 1907, p. 348 (listed); Amer. 

 Journ. Sci., ser. 4, vol. 32, 1911, p. 130 (significance of distinctive characters); Die Fauna 

 Sudwest-Australiens, vol. 3, Lief. 13, 1911, p. 441 (Australian tropical species occurring south 

 to Dampier Archipelago and Cape York), p. 443 (range on east coast), p. 444 (range on west 

 coast), p. 446 (summary of west Australian records); Mem. Australian Mus., vol. 4, 1911, 

 p. 712 (identity with Hyponome sarsi), p. 717 (known from Australia), p. 721 (occurs south to 

 Cape York), p. 724 (peculiar to north Australia); p. 734 (in key), p. 761 (synonymy; charac- 

 ters; Australian records; range); Smithsonian Misc. Coll., vol. 60, No. 10, 1912, p. 11 (synonym 

 of Z. microdiscus) ; Crinoids of the Indian Ocean, 1912, p. 3 (identity of Hyponome sarsi), p. 33 

 (synonym of microdiscus) , p. 104 (synonymy; summary of known records); Ree. Western 

 Australian Mus., vol. 1, pt. 3, 1914, p. 123 (synonym of microdiscus) . 



Zygomctra miciodiscus A. H. Clark, Amer. Journ. Sci., ser. 4, vol. 32, p. 130 (significance of dis- 

 tinctive characters). 



Zygometra mcrtoni Reichensperqer, Abh. Senck. naturf. Ges., vol. 35, Heft 1, 1913, p. 82 (Aru 

 Islands), p. 90 (description and comparisons; localities), fig. 6, p. 91 (proximal pinnules). — 

 A. H. Clark, Unstalked crinoids of the Sifcoga-Exped., 1918, p. 59, footnote 1 (synonym of 

 microdiscus) . 



Zygomctra microdisca H. L. Clark, Echinoderm fauna of Torres Strait, 1921, pp. 5, 7 (history), 

 p. 20 (range). 



Zygometra cf. microdiscus Gislen, Zool. Bidrag Uppsala, vol. 9, 1924, p. 271 {Hyponome sarsi; food). 



Diagnostic features. — A largo species with usually 65-100 arms from 85 to 145 

 mm. long, and the longest cirri with usually 45-70 segments; all, or nearly all, the 

 division series beyond the IBr series are 4(3+4); and the proximal pinnules are stout 

 at the base and very long, 20-32 mm. in length, with 25-60 segments. 



Description. — The centrodorsal is large and prominent, varying from thick dis- 

 coidal with a slightly convex dorsal pole about 3 mm. in diameter to more or less 

 hemispherical. The cirrus sockets are arranged in two to four (usually two or three) 

 irregular marginal rows. 



