PART 5 A MONOGRAPH OF THE EXISTING CRINOIDS 51 



e 1 . Cirri about LXX when the arm length is only 30 mm.; P, and P 2 with about the same 

 number of segments (Hawaiian Islands; 270-298 meters). 



Argyrometra crispa (p. 97) 



e-. Cirri only over L when the arm length exceeds 100 mm.; P 2 with fewer segments than PI 

 (Moluccas, Philippines and China to the Society Islands and southern Australia; 



0-397 meters) Euantedon (p. 99) 



d 1 . PI with 25 to 50 segments, rarely as few as 20. 



e 1 . Brachials more or less thickened at their distal edges (Ceylon to the Society Islands; 



0-48 meters) Mastigometra (p. 106) 



e 2 . Brachials not flared at their distal edges (western Sweden, Norway, the Faeroe Islands 



and southwest of Iceland; 27-326 meters) Antedon petasus (p. 130) 



c. 2 PI similar in size to Pj, not distinctly smaller (north-east and tropical Atlantic, the Mediter- 

 ranean, Arabian Sea to southern Japan and southern Australia, 0-932 meters). 



Antedon (p. Ill) 



Genus TOXOMETRA A. H. Clark 



Toxometra A. H. CLARK, Proc. U.S. Nat. Mus., vol. 39, 1911, p. 560 (diagnosis; type T. paupera; 

 referred to the Antedoninae) ; Crinoids of the Indian Ocean, 1912, p. 9 (absent from Australia), 

 p. 10 (absent from Japan; reason), p. 11 (absent from the west coast of the Malay peninsula 

 and further west), p. 25 (range), p. 63 (in key), p. 232 (original reference; type); in Springer 

 and Clark, Zittel-Eastman's Paleontology, 1913, p. 237 (in the Antedoninae); Journ. Washington 

 Acad. Sci., vol. 7, 1917, No. 5, p. 127 (referred to the Antedoninae); No. 16, p. 506 (in key; 

 range); Unstalked crinoids of the Siboga-Exped., 1918, p. 197 (in key; range), p. 210. GISLN, 

 Nova Acta Reg. Soc. Sci. Upsaliensis, ser. 4, vol. 5, No. 6, 1922, p. 7 (distribution), pp. 129, 

 130, 131. 



Monilimetra H. L. CLARK, Mem. Mus. Comp. Zool., vol. 55, 1938, p. 47 (diagnosis; type M. nomima 

 sp. nov.); Echinoderm fauna of Australia, 1946, p. 60 (in key), p. 62 (genus limited to N.W. 

 Australia; key to species). 



Diagnosis. A genus of Antedoninae in which P 3 is much the longest and stoutest 

 pinnule on the arm; the distal ends of the cirrus segments do not overlap the bases of 

 those succeeding and the dorsal length of the outer 4 to 6 cirrus segments is about 

 equal to their proximal width. 



Type species. Toxometra paupera A. H. Clark, 1911. 



Geographical range. From Flores to Negros and Mindanao, Philippines, and north- 

 west Australia. 



Bathymetrical range. From the shore line down to 510 meters. 



Thermal range. From the temperature of the tropical reefs down to 11.95C. 



Remarks [by A. M. C.]. Mr. A. H. Clark included, without comment, the nominal 

 genus Monilimetra H. L. Clark, 1938, in the synonymy of Toxometra. Since it also 

 shares with Dorometra the character of the enlarged P 3 some comparison is called for 

 as justification for this move, particularly as it was with Dorometra that H. L. Clark 

 gave a comparison. The cirrus segments of Toxometra paupera are distinguished from 

 those of the species of Dorometra by the absence of flared and overlapping distal ends 

 and the relatively shorter distal segments. Monilimetra bicolor appears to approach 

 Dorometra in these characters, to judge from H. L. Clark's figures, but the other three 

 species of Monilimetra have cirri approximating more to those of Toxometra. No men- 

 tion was made by H. L. Clark of spinous distal productions of the brachials in any of 

 the species of Monilimetra, which are therefore taken to have smooth brachials like 

 those of Dorometra rather than flared spinous ones like Toxometra paupera. However, 

 this character probably has no great reliability. 



556-622 67 5 



