A MONOGRAPH OF THE EXISTING CRINOIDS 99 



HAMANN, Bronns Klassen und Ordnungen des Tier-Reichs, vol. 2, Abt. 3, 1907, p. 1577 (listed). 

 A. H. CLARK, Mem. Australian Mus., vol. 4, 1911, p. 714 (of Alert report = Z. elegans), p. 716 

 (known from Australia), p. 720 (of Doderlein = Z. elegans); Crinoids of the Indian Ocean, 

 1912, p. 31 (of Bell, 1884 = Z. elegans), p. 33 (of P. H. Carpenter, 1888 = Z. elegans + Z. 

 comata), p. 36 (of P. H. Carpenter, 1889 = Z. comata), p. 39 (of Doderlein, 1898 = Z. elegans). 



Antedon fluctuans P. H. CARPENTER, Challenger Reports, Zoology, vol. 11, part 32, 1884, p. 280. 

 VON GRAFF, Challenger Reports, Zoology, vol. 10, pt. 27, 1884, pp. 16, 18, 57 (Challenger station 

 190; myzostomes); vol. 20, pt. 61, 1887, p. 7 (Torres Strait, 10 fathoms, Alert; myzostomes). 

 P. H. CARPENTER, Challenger Reports, Zoology, vol. 26, pt. 60, 1888, p. 94 (description; Chal- 

 lenger station 190; Torres Strait, Alert; notes), pp. 264-266 (identity with elegans), pi. 8, figs. 

 1, 2. BRAUN, Centralbl. fur Bakt. und Parasitenk., vol. 3, 1888, p. 186 (myzostomes). 



Zygometra elegans A. H. CLARK, Smithsonian Misc. Coll., vol. 50, 1907, p. 348 (listed); Zool. Anz., 

 vol. 34, 1909, p. 367 (Mermaid Strait); Amer. Journ. Sci., ser. 4, vol. 32, 1911, p. 130 (signifi- 

 cance of distinctive characters); Die Fauna Siidwest-Australiens, vol. 3, Lief. 13, 1911, p. 441 

 (tropical Australian species occurring south to Perth and Port Curtis), p. 443 (range on the 

 east coast), p. 444 (range on the west coast), p. 458 (localities), p. 466 (association with other 

 species); Mem. Australian Mus., vol. 4, 1911, p. 717 (known from Australia), p. 722 (occurs 

 south to Port Curtis), p. 723 (Mermaid; Baudin Island), p. 724 (peculiar to north Australia), 

 p. 734 (in key), p. 762 (synonymy; characters; localities); Proc. U. S. Nat. Mus., vol. 43, 

 1912, pp. 385, 393 (localities); Crinoids of the Indian Ocean, 1912, pp. 31, 33, 39 (identity of 

 records), p. 104 (synonymy; summary of records); Proc. Biol. Soc. Washington, vol. 26, 1913, 

 p. 181 (comparison with Z. comata); Smithsonian Misc. Coll., vol. 61, No. 15, 1913, p. 21 (pub- 

 lished references to specimens in the B. M.; localities; notes). ALEXANDER, Rec. Western 

 Australian Mus., vol. 1, pt. 3, 1914, p. 108 (between Fremantle and Geraldton). A. H. 

 CLARK, Rec. Western Australian Mus., vol. 1, pt. 3, 1914, p. 114 (collected by the Endeavour in 

 Western Australia; occurrence near Perth confirmed), p. 121 (between Fremantle and Gerald- 

 ton; characters of the specimens; comparison with related species); Internat. Rev. gesamt. 

 Hydrobiol. und Hydrogr., 1915, pp. 224 ff. (detailed account of distribution in Australia). 

 H. L. CLARK, Biol. Results Fishing Exper. F. I. S. Endeavour, 1909-14, vol. 4, part 1, 1916, 

 p. 18 (localities; notes). HARTMETER, Mitt. zool. Mus. Berlin, vol. 8, Heft 2, 1916, p. 23o 

 (Western Australia, in Hamburg Mus.; Mermaid Strait, No. 2963). A. H. CLARK, Unstalked 

 crinoids of the Siboga-TZxped., 1918, p. 59 (in key; range). GISLEN, Kungl. Svenska Vet.-akad. 

 Handl., vol. 59, No. 4, 1919, p. 3 (variety of Z. microdiscus) . H. L. CLARK, Echinoderm fauna 

 of Torres Strait, 1921, pp. 6, 7 (history), p. 20 (range). GISLEN, Zool. Bidrag Uppsala, vol. 

 9, 1924, p. 41 (details of arms), p. 44 (reversion); Kungl. Fysiogr. Sallsk. Handl., new ser., vol. 

 45, No. 11, 1934, pp. 37, 40. A. H. CLARK, Temminckia, vol. 1, 1936, p. 300 (Amboina; 

 notes). H. L. CLARK, Mem. Mus. Comp. Zool., vol. 55, 1938, p. 31 (off Norwest Islet, Capri- 

 corn group, 6 fathoms; Darwin, near Shell Islands, 3-6 fathoms; Broome; notes). 



Zygometra microdiscus var. elegans GISLEN, Kungl. Svenska Vet.-Akad. Handl., vol. 59, No. 4, 

 1919, p. 3 (listed), p. 5 (Station 11), p. 19 (detailed discussion and description of specimens), 

 pi. 1, fig. 5. 



Zygometra microdiscus elegans GISLEN, Zool. Bidrag Uppsala, vol. 9, 1924, p. 77 (syzygies). 



Diagnostic features. A large species with usually 35-45 arms 70 to 110 mm. long, 

 and the longest cirri with usually 35-45 segments; the IIIBr and following division 

 series are mostly 2, the IIIBr series being commonly 2 internally and 4 (3+4) exter- 

 nally, as in the species of Himerometra; the proximal pinnules are slender and moderate 

 in length, P D being 14-18 mm. long with 27-40 segments. 



Description. The centrodorsal varies from large and flattened hemispherical to 

 small and rather thin discoidal, being usually large and thick discoidal with the dorsal 

 pole slightly concave or almost flat, 2.5-5 (usually 3-5) mm. in diameter. The 

 cirrus sockets are arranged in 2 or 3, sometimes more, crowded and irregular marginal 

 rows. 



