A MONOGRAPH OF THE EXISTING CRINOIDS 225 



Genus HETEROMETRA A. H. Clark 



Comatula (part) AUDOUIN, in Savigny, Description de 1'figypte, 1817 (1826), p. 205, and following 

 authors. 



Alecto (part) J. MILLER, Monatsber. preuss. Akad. Wiss., 1841, p. 185. 



Comatula (Alecto) (part) J. MULLER, Monatsber. preuss. Akad. Wiss., 1846, p. 178. 



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

 authors. 



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



Amphimetra (part) A. H. CLARK, Proc. Biol. Soc. Washington, vol. 22, 1909, p. 7. 



Craspedomelra (part) A. H. CLARK, Proc. U. S. Nat. Mus., vol. 37, 1909, p. 31. 



Heterometra A. H. CLARK, Proc. Biol. Soc. Washington, vol. 22, 1909, p. 11 (diagnosis; genotype 

 Antedon guinduplicava P. H. Carpenter, 1888); Amer. Nat., vol. 43, 1909, p. 254 (represented in 

 the Red Sea); Zool. Anz., vol. 34, 1909, p. 367 (arm division similar to that of Antedon fluctuant 

 [Zygometra comata]) ; Proc. Biol. Soc. Washington, vol. 22, 1909, p. 175 (referred to the Himero- 

 metrinae); A. H. CLARK, Mem. Australian Mus., vol. 4, 1911, pp. 731, 732 (in keys), p. 734 

 (key to the Australian species), p. 767 (original reference; characters; range); Crinoids of the 

 Indian Ocean, 1912, p. 9 (possesses additional species in Australia), p. 10 (absent from Japan; 

 reason), p. 11 (represented in the Ceylon region; this the western limit of the large and highly 

 multibrachiate species), p. 12 (represented in Red Sea region and in southeast African region), 

 p. 21 (range in detail), p. 56 (in key), p. 120 (original reference; type); Die Fauna Sudwest- 

 Australiens, vol. 4, Lief. 6, 1913, p. 311 (discussion of the small species and comparison with 

 the small species of Zygometra'); Unstalked crinoids of the S-iboga-Exped., 1918, p. 72 (in key; 

 range), p. 75 (key to the included species). GISLEN, Kungl. Fysiogr. Sallsk. Hand!., new ser., 

 vol. 45, No. 11, 1934, pp. 45, 46, 48. A. H. CLARK, Temminckia, vol. 1, 1936, p. 305. GISLEN, 

 Kungl. Fysiogr. Sallsk. Lund Forh., vol. 7, No. 1, 1936, p. 17. 



Diagnosis. A genus of Himerometridae in which the cirri are of moderate 

 length with the distal segments always bearing dorsal tubercles or spines and the 

 terminal claw always strongly curved; the distal cirrus segments are usually shorter 

 than the proximal, or both distal and proximal cirrus segments are short ; P! is shorter 

 and slenderer than P 2 , and P 2 is usually shorter and more slender than P 3 ; the enlarged 

 proximal pinnules are much elongated, slender or rather stout, smooth, basally cari- 

 nate, or with the outer segments armed at the distal end with spines or flangelike 

 projections; there are more than 10 arms. 



In a few species 10-armed individuals occur, but these are always distinguishable 

 from the species of Amphimetra by the characteristic proximal pinnules which are 

 strongly keeled basally or have their outer segments provided distally with spines or 

 flangelike projections. 



Geographical range. From southern Japan southward to Port Curtis, Queens- 

 land, and Baudin Island, northwestern Australia, and westward to Madagascar and 

 the eastern coast of Africa from the Red Sea south to Zanzibar and Bagamoyo. 



Bathymetrical range. From the low-tide mark down to 111 meters. The species 

 of Heterometra are especially characteristic of the zone from the low-tide mark down 

 to about 50 meters. Of the 25 species only 7 are known from a greater depth than 

 50 meters, and all but 4 have been taken in shore collecting. 



Remarks. The genus Heterometra includes a rather heterogeneous assemblage 

 of 25 species. In the genus as a whole all the characters of the cirri, pinnules, and 

 arms are exceedingly variable and more or less overlap those of the other genera of 

 the family Himerometridae. The species of the genus Heterometra are therefore 

 recognizable not so much by a special and distinctive generic combination of charac- 



