A MONOGRAPH OF THE EXISTING CRINOIDS 361 



Genus STROTOMETRA A. H. Clark 



Antedon (part) P. H. CARPENTER, Challenger Reports, Zoology, vol. 26, pt. 60, 1888, p. 127, and 

 following authors. 



Charitomelra (part) A. H. CLARK, Smithsonian Misc. Coll., vol. 50, pt. 3, 1907, p. 361. 



Slrotometra A. H. CLARK, Proc. Biol. Soc. Washington, vol. 22, 1909, p. 19 (diagnosis; genotype 

 Antedon hepburniana 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, the Andamans, and farther 

 west), p. 25 (range), p. 60 (in key), p. 226 (original reference; type); Unstalked criuoids of the 

 Siboga-Exped., 1918, p. 172 (in key; range), p. 191 (key to the included species). GISLEN, Ark. 

 Zool., vol. 19, No. 32, Feb. 20, 1928, p. 9; Kungl. Fysiograf. Sallsk. Handl., new ser., vol. 45, 

 No. 11, 1934, p. 18. 



Diagnosis. The genital pinnules have the third and fourth, third-fifth, or fifth- 

 eighth segments much broadened, the abruptly narrower tip being shorter than the 

 expanded portion; the division series and arm bases are more or less recumbent, their 

 profile in lateral view making a wide angle with the dorsoventral axis; there are not 

 more than 15 cirrus segments, seldom more than 13; and the size is small, the arms 

 not exceeding 75 mm., and rarely being more than 45 mm. in length. 



Geographical range. From Timor and the Kei Islands northward to southwestern 

 Japan. 



Bathymetrical range. From 180 to 1,165 (?1,264) meters. 



Thermal range. One record from southwestern Japan, 11.28 C. 



History. The genus Strotometra was established in 1909 with the genotype Antedon 

 hepburniana A. H. Clark, 1907, including also Carpenter's Antedon parvipinna, both 

 of which had been previously referred to Charitometra. The status of the genus has 

 remained unchanged except for the addition of two new species, ornatissimus and 

 priamus, in 1912. 



KEY TO THE SPECIES IN THE GENUS STROTOMETRA 



a 1 . Distal border of the second brachial everted, standing out at right angles to the dorsoventral 

 axis of the arm as an enormous thin rounded or fan-shaped crest with a rounded or broadly 

 scalloped edge, sometimes divided in the middle, which may reach 1.5 mm. in height, the height 

 being three or four times the greater (outer) length of the ossicle; the fourth brachial (epizygal 

 of the first syzygial pair) has a similar crest nearly, if not quite as large; the fifth brachial has a 

 crest about half as high and more irregular; the sixth has a strongly produced and thickened 

 distal edge which is coarsely scalloped; the following brachials are of the normal type with 

 slightly produced and finely spinous distal borders (east of the northeastern end of Celebes; 



1,165-1,264 meters) ornatissimus (p. 326) 



a 3 . None of the brachials have everted and extravagantly developed distal borders. 



6'. Cirri slender with all the segments beyond the second much longer than broad, the longest 

 nearly three times as long as the median width, and moderately constricted centrally; genital 

 pinnules with the fifth-eighth segments broadened, so that the expanded portion is preceded 

 by a distinct peduncle; no carination of the IBr series and arms (Kei Islands to southwestern 



Timor; 245-595 meters) priainus (p. 363) 



ti 3 . Cirri short and stout, the longest segments very little or not at all longer than broad and not 

 constricted centrally; genital pinnules with the third-fourth or third-fifth segments broadened 

 so that the expanded portion appears sessile; IBr series and arms more or less distinctly 

 carinate. 



c 1 . PI with 20-22 segments, 6 mm. long; pinnules in the proximal portion of the arms smooth or 

 nearly so; larger, arms 60-75 mm. long; cirri with 11-15 segments (Kei Islands to south- 

 western Timor; 245-520 meters) parvipinna (p. 365) 



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