A MONOGRAPH OF THE EXISTING CRINOIDS 221 



China Sea south of Pratas Reef (lat. 21°10' N., long. 117°30' E.); 704 meters; 

 bottom temperature 7.2° C; May 22, 1911; Captain Suensson (1, CM.). 



Geographical range. — From the Halmahera Sea to the northern part of the South 

 China Sea in the vicinity of Pratas Reef. 



Bathymetrical range. — From 1 18 to 704 meters. 



Thermal range. — From 7.2° to 15.0° C. 



History. — This species was first described under the name of Pachylometra fragilis 

 in 1912 from a specimen from Siboga station 166. In 1916 it was made the type of 

 the new genus Monachometra, and in 1918 in my memoir on the unstalked crinoids 

 of the Siboga Expedition Monachometra fragilis was described in detail and a second 

 specimen was recorded from Albatross station 5110. 



In 1924 Prof. Tors ten Gisl6n wrote that Monachometra cf. fragilis has the thir- 

 teenth brachial the first with the pinnule-bearing side longer than the other, and that 

 the distal angle of the IBr axillary measures 145°. He figured a postradial series of 

 his specimen showing a IBr series followed by a single arm ending with the fourteenth 

 brachial on the left and on the right a IIBr series with the left arm carried to the 

 fifteenth brachial. This postradial series represents not Monachometra fragilis, but 

 Parametra orion. 



In 1927 Professor Gislen wrote I had informed him that the opposing spine of 

 Monachometra fragilis is double, Hke that of Diodontometra bocki, and that there is a 

 specimen of M. fragilis in the Uppsala Museum which had permitted him to make 

 comparisons with a new species that he described as Monachometra mortenseni. He 

 gave no further information regarding the specimen at Uppsala, but his Monachometra 

 mortenseni is in reality Parametra orion. In 1934 Gislen distinguished two different 

 types of arm division which he called Monachometra fragilis types I and II. Both 

 are from the specimen in the Uppsala Museum, which appears to represent Parametra 

 orion. 



Genus CHLOROMETRA A. H. Clark 



Chlorometra A. H. Clark, Proc. Biol. Soc. Washington, vol. 22, 1909, p. 21 (diagnosis; genotype 

 Antedon garreltiana A. H. Clark, 1907); Crinoids of the Indian Ocean, 1912, p. 9 (absent from 

 Australia), p. 11 (absent from the west coast of the Malay Peninsula and from farther west), 

 p. 25 (range), p. 60 (iu key), p. 225 (original reference; type); Die Crinoiden der Antarktis, 1915, 

 p. 125 (certain species of this genus show the characters of Anlhomclra adriani); Unstalked 

 crinoids of the Siboga-Exped., 1918, p. 174 (in key; range), p. 190. — Gisl£n, Kungl. Fysiogr. 

 Sallsk. Handl., new ser., vol. 45, No. 11, 1934, pp. 18, 20. 



Diodontometra GislIsn, Nova Acta Reg. Soc. Sci. Upsaliensis, ser. 4, vol. 5, No. 6, 1922, p. 121 (char- 

 acters; only included species D. bocki); Zool. Bidrag Uppsala, vol. 9, 1924, p. 280; Vid. Medd. 

 Dansk Nat. Foren., K0benhavn, vol. 83, 1927, p. 38; Ark. Zool., vol. 19, No. 32, Feb. 20, 1928, 

 p. 8; Kungl. Fysiogr. Sallsk. Handl., new ser., vol. 45, No. 11, 1934, pp. 20, 21. 



Diagnosis. — The genital pinnules have the third to fifth or third to sixth seg- 

 ments flattened and expanded with winglike borders, the portion of the pinnules 

 beyond being abruptly narrower and shorter than the expanded portion; the centro- 

 dorsal is sharply conical, higher than broad at the base, with the cirrus sockets in 5 

 midradial single or partially double columns; there are 14 to 20 arms about 60 mm. 

 long; and the opposing spine is forked. 



Geographical range. — From southwestern Japan to the Bonin Islands. 



Bathymetrical range. — From 165 to 210 meters. 



