A MONOGRAPH OF THE EXISTING CRINOIDS 203 



species are readily distinguished from the others of the genus (Cyllometra) by the 

 small number of cirrus segments. 



In a paper on the crinoids of the Gazelle expedition published on June 1, 1909, 

 Cyllometra studeri was briefly recorded without comment. In a paper on the crinoids 

 of the coasts of Africa published in 1911 I compared the arms of C. smderi with those 

 of the new species Decametra mobiusi. Later in 1911 I mentioned Decametra studeri 

 in my report upon the crinoids of the Hamburg Southwest Australian Expedition, and 

 also in my memoir on the crinoids of Australia. In my paper on the crinoids of the 

 Berlin Museum published in 1912 I listed Decametra studeri, giving the locality and 

 a reference to the paper on the crinoids collected by the Gazelle. In my memoir on 

 the crinoids of the Indian Ocean published in 1912 I listed Decametra studeri and gave 

 its synonymy and range. The range of D. studeri was considered in detail in a paper 

 on the distribution of crinoids on the coasts of Australia published by the author in 

 191-5. 



Dr. Robert Hartmeyer hi 1916 published a note on Decametra studeri, giving the 

 catalog number, 6381, of the type specimen in the Berlin Museum. 



In my report upon the crinoids of the Siboga expedition published in 1918 I 

 included studeri in the key to the species of Decametra and gave the range. 



DECAMETRA INFORMIS (P. H. Carpenter) 



PLATE 24, FIGURE 125 



Antedon informis P. H. CARPENTER, Challenger Reports, Zoology, vol. 26, pt. 60, 1888, p. 205 (de- 

 scription; Challenger station 208), pi. 33, fig. 3. HARTLAUB, Nova Acta Acad. German., vol. 

 58, No. 1, 1891, p. 42 (compared with A. [Pelasometra] clarae). HAMANN, Bronns Klassen und 

 Ordnungen des Tier-Reiehs, vol. 2, Abt. 3, 1907, p. 1579 (listed). A. H. CLARK, Crinoids of 

 the Indian Ocean, 1912, p. 33 (= Decametra informis). H. L. CLARK, Echinoderm fauna of 

 Australia, 1946, p. 52. 



Cyllometra informis A. H. CLARK, Smithsonian Misc. Coll., vol. 50, pt. 3, 1907, p. 357 (listed); 

 Proc. Biol. Soc. Washington, vol. 22, 1909, p. 6 (listed) , p. 77 (arms compared with those of 

 C. [Decametra] rnollis), p. 88 (compared with C. [Decametra] studeri; north end of Samal Island, 

 Philippines, 23 fms.). 



Decametra informis A. H. CLARK, Proc. U. S. Nat. Mus., vol. 40, 1911, p. 32 (arms compared with 

 those of D. modica); vol. 43, 1912, p. 400 (Singapore; description); Crinoids of the Indian 

 Ocean, 1912, p. 33 (identity) p. 164 (synonymy; localities); Smithsonian Misc. Coll., vol. 61, 

 No. 15, 1913, p. 34 (published reference to the specimen in the B. M.; Challenger station 208); 

 Unstalked crinoids of the Siboga-~Exped., 1918, p. 118 (in key; range), p. 123 (Albatross station 

 5249); Temminckia, vol. 1, 1936, p. 309 (Sipankot; notes), pi. 8, fig. 8. H. L. CLARK, Echino- 

 derm fauna of Australia, 1946, p. 52. 



Diagnostic features. The cirri are 7 mm. long with 14-18 segments; P t and P 2 

 have 10-12 segments, the outermost with small tufts of spines on the distal edge; 

 P 2 is longer and stouter than PI; the arms are 30-40 mm. long. 



Description. The centrodorsal is discoidal with a smooth dorsal surface and 

 marginal cirri. 



The cirri are about XII, 15-18. The segments are as broad as or broader than 

 long, most of them with a slight elevation in the middle of the dorsal edge. The 

 penultimate segment has a faint opposing spine. 



The radials are partially visible. The IBr, are oblong with a rounded dorsal 

 surface and are but slightly united laterally. The IBr 2 (axillaries) are also rounded, 

 short, and widely rhombic. 



