A MONOGRAPH OF THE EXISTING CRINOIDS 61 



Prof. Torsten Gisl6n in 1938 gave brief notes on three dried specimens from 

 Pieter Faure No. 12884 and more detailed notes on a large specimen from Dr. Th. 

 Mortensen's station 25. Noting that the expanded genital pinnules in Mortensen's 

 specimen are closely reminiscent of Charitometra, he said that provided it is not a 

 young individual of Pachylometra sclateri, to which he referred his specimens though 

 with considerable doubt, it is a new species which may probably be most correctly 

 ranged within the 10-armed genus Charitometra. 



Genus OLIGOMETRIDES A. H. Clark 



Comatula (part) LAMARCK, Histoire naturelle des animaux sans vertebres, vol. 2, 1816, p. 535. 



Aleclo (part) J. MULLER, Arch. Naturg., 1841, vol. 1, p. 142. 



Antedon (part) P. H. CARPENTER, Trans. Linn. Soc. (Zool.), ser. 2, vol. 2, 1879, p. 29, and following 

 authors. 



Milberti group (part) P. H. CARPENTER, Challenger Reports, Zoology, vol. 26, pt. 60, 1888, p. 376. 



Himerometra (part) A. H. CLARK, Smithsonian Misc. Coll., vol. 50, pt. 3, 1907, p. 356. 



Oligomelra (part) A. H. CLARK, Proc. Biol. Soc. Washington, vol. 21, 1908, p. 126. 



Oligometrides A. H. CLARK, Smithsonian Misc. Coll., vol. 61, No. 15, 1913, p. 37 (no diagnosis and 

 no genotype mentioned; name used in combination with [Comatula] adeonae Lamarck); Internat. 

 Rev. gesamt. Hydrobiol. und Hydrogr., 1914, p. 4 and following (represents Analcidometra; 

 range and its significance) ; Beitrage zur Kenntnis der Meeresfauna Westafrikas, Echinod. II, 

 Crinoidea, 1914, p. 309 (corresponds to Analcidometra); Journ. Washington Acad. Sci., vol. 5, 

 No. 1, 1915, p. 9 (confined to Australia; most closely related to Analcidometra); Die Crinoiden 

 der Antarktis, 1915, p. 167 (range), p. 181 (range; represented in the Atlantic by Analcido- 

 metra); A. H. CLARK, Journ. Washington Acad. Sci., vol. 6, No. 5, 1916, p. 116 (closely related 

 to Analcidometra and Austromelra) ; Unstalked crinoids of the 5i6ojo-Exped., 1918, p. Ill (in 

 key), p. 126. GISLEN, Kungl. Svenska Vet. Handl., vol. 59, No. 4, 1919, p. 33 (discussion); 

 Nova Acta Reg. Soc. Sci. Upsaliensis, ser. 4, vol. 5, No. 6, 1922, p. 90; Zool. Bidrag Uppsala, vol. 9, 

 1924, p. 51 (obliquity of the brachials), p. 84 fsyzygies), p. 89 (articulations). A. H. CLARK, 

 Journ. Linn. Soc. (Zool.), vol. 36, No. 249, April 1929, p. 643. GISLEN, Kungl. Fysiogr. Sallsk. 

 Handl., new ser., vol. 45, No. 11, 1934, p. 18. H. L. CLARK, Echinoderm fauna of Australia, 

 1946, p. 48 (in key), p. 50. 



Oligemetrides GISLEN, Kungl. Svenska Vet. Handl., vol. 59, No. 4, 1919, p. 28. 



Diagnosis. A genus of Colobometridae in which the 10 arms are 35-70 (usu- 

 ally about 50) mm. long; the cirri are short and stout with 17-32 (usually about 20) 

 segments, each bearing dorsally two transverse ridges, a proximal and a distal; P 1( 

 P 2 , and P 3 are smooth, enlarged, and stiffened, decreasing in length from P,, with 

 9-20 (usually 10-13) segments; all the pinnules are present, and the genital pinnules 

 are not broadened. 



This genus is closely allied to Iconometra from which it differs in having two 

 transverse ridges on the cirrus segments, and in having P! the longest pinnule. 



Geographical range. Aru Islands and northern Australia south to Port Curtis, 

 Queensland, and Cape Jaubert, Western Australia. 



Bathymetrical range. From the shore line down to 22 (?37) meters. 



History. The only known species of this genus was described by Lamarck as a 

 species of Comatula in 1816. It was transferred to the genus Alecto by Johannes 

 M tiller in 1841. In 1879 it was placed by Dr. P. H. Carpenter in the genus Antedon. 

 In 1888 Carpenter placed Lamarck's Comatula adeonae and Bell's Antedon bidens 

 described in 1884 a synonym of adeonae in a list of 10-armed species that did not 

 seem to fit into any of the specific groups established by him within the genus Antedon; 



