PART 5 A MONOGRAPH OF THE EXISTING CRINOIDS 473 



comatulids from off Cuba, when he described several new species of Caryometra, and 

 was therefore reached, as far as the Indo-Pacific species were concerned, by comparison 

 of the published descriptions. These are somewhat misleading, particularly Carpenter's 

 description of angustiradia, in which the very distinct columnar arrangement of the 

 cirrus sockets \vith interradial spaces was not made clear. The crowded and rather 

 irregular arrangement of the sockets in robusta is so much at variance with this, as 

 well as the laterally expanded division series and lower brachials, that I think it 

 outweighs the similarity in the cirri themselves. On the other hand, the genus Perometra 

 and particularly P. afra (oddly enough another of the very few Macrophreates with 

 more than 10 arms like angustiradia) has many similarities to robusta, particularly the 

 possession of papillae on the apex of the centrodorsal, pinnules of very similar type, 

 cirri of comparable length, proportions, number and arrangement as well as laterally 

 flanged proximal ossicles with large synarthrial tubercles. Of the other two species of 

 Perometra, both of which do have only 10 arms, diomedeae usually lacks P^ and the 

 single known specimen of pusilla has only XV cirri. Both these species have the 

 outer segments of Pj lacking the spinous flared distal ends developed conspicuously 

 by robusta. 



Genus ERYTHROMETBA A. H. Clark* 



Anledon (part) A. H. Clark, Proc. U.S. Nat. Mus., vol. 33, 1907, p. 146. 



Cyllomelra (part) A. H. Clark, Smithsonian Misc. Coll., vol. 50, part 3, 1907, p. 357. 



Erythrometra A. H. Clark, Proc. Biol. Soc. Washington, vol. 21, 1908, p. 126 (diagnosis; type species 

 Aniedon ruber A. H. Clark, 1907), p. 134 (pinnulation), p. 136 (referred to Antedonidae) ; Proc. 

 U.S. Nat. Mus., vol. 34, 1908, p. 211 (referred to Antedonidae, restricted), p. 212 (occurs in 

 Japan), p. 316; Amer. Nat., vol. 42, No. 503, 1908, p. 725 (color); Proc. Biol. Soc. Washington, 

 vol. 22, 1909, p. 176 (referred to Perometrinae) ; Proc. U.S. Nat. Mus., vol. 40, 1911, p. 10 (repre- 

 sented in West Indies by Ilypalometra); Amer. Journ. Sci., ser. 4, vol. 32, 1911, p. 129 (charac- 

 teristic of Japanese fauna; significance); Crinoids of the Indian Ocean, 1912, p. 9 (does not occur 

 in area of maximum intensity of the East Indian fauna), p. 10 (confined to Japan), p. 17 (only 

 known from Japan), p. 26 (confined to southern Japan; 55-105 fms.), p. 61 (in key), p. 233 

 (original reference; type); Smithsonian Misc. Coll., vol. 65, No. 10, 1915, pp. 16 and following 

 (phylogenetical study); Journ. Washington .\cad. Sci., vol. 7, 1917, No. 5, p. 127 (referred to 

 Perometrin.ae) ; No. 16, p. 507 (in key; range); Unstalked crinoids of the Siboga-Exped., 1918, 

 p. 234 (in key; range), p. 235 (key to the included species). — Gisl£n, Nova Acta Reg. Soc. Sci. 

 Upsaliensis, ser. 4, vol. 5, No. 6, 1922, p. 140; Ark. Zool., vol. 19, No. 32, 1928, p. 12; Kungl. 

 Fysiogr. Sallsk. Ilandl., new ser., vol. 45, No. 11, 1934, p. 18. 



Diagnosis. — The elements of the IBr series and lower brachials are never in close 

 lateral contact with and flattened against their neiglibors; the borders of these ossicles 

 are alwaj-s more or less tubercular; the interradial and interbrachial portions of the 

 perisome bear numerous prominent rounded calcareous nodules, which are not in lateral 

 contact; and P^ is usually absent. The 10 arms are up to 60 mm. long. 



The most characteristic feature of the species of this genus is the occurrence of 

 numerous conspicuous interradial and interbrachial plates. The color in life seems 

 to be always red or orange. 



Type species. — Antedon ruber A. H. Clark, 1907. 



Geographical range. — From the Moluccas and Kei Islands north to southern Japan. 



Bathymetrical range. — From 100 (?95) to 274 meters. 



Thermal range.— From 11.11° C. to 15.89° C. 



* See footnote on p. 457 



