74 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



e\ Pi not delicate nor weak, with the first 2 segments not noticeably enlarged; Po like Ps (vol. 



1, pt. 2, fig. 280, p. 213; figs. 317, 318, p. 318), or, more rarely, like P, (vol. 1, pt. 2, 



figs, 303, 304, p. 223), never especiaUy distinguished: disk sunken within the division 



series, with the ventral surface concave, flat, or slightly convex, and thickly beset 



with isolated plates (vol. 1, pt. 2. figs. 743-746, p. 349); color usually plain, yellow, 



brownish, or purplish, sometimes with the basal portion darker, seldom blotched. 



/'. Cirri usually long and slender, rarely of moderate length and rather stout, composed 



of usually more than 25 segments, of which the distal are much shorter than the 



earlier and bear conspicuous dorsal spines or carinate processes; surface of the 



shorter distal segments always light in color and highly polished; a well-marked 



transition segment usually present Thalassometridae (pt. 4). 



gK P, stouter and longer than P2 (vol. 1, pt. 2, figs. 283, 284, p. 215; fig. 1050, pi. 13), 

 though sometimes not much so; color plain (vol. 1, pt. 2, figs. 210-225, p. 150 

 and following; fig. 1140, pi. 22; fig. 1345, pi. 53) (Japan, Aleutian, Hawaiian, and 

 Galapagos Islands to Tasmania and westward to east Africa; in the Atlantic 

 north to the Bay of Biscay and the Caribbean Sea; chiefly in deep water, but a 



few species are sublittoral) Thalassometrinae (pt. 4). 



g\ Pi similar to Pj, but shorter (vol. 1, pt. 2, fig. 280, p. 213; fig. 285, p. 215); cirri 

 exceedingly long; color sometimes blotched (vol. 1, pt. 2, figs. 203-208, p. 137 

 and following; fig. 1346, pi. 53) (Japan to Tasmania and the Bay of Bengal; 



sublittoral, in south Australia also littoral) Ptilometrinae (pt. 4). 



p. Cirri usually short, stout, and strongly curved, rarely more or less elongated, com- 

 posed of usually fewer than 25 segments, of which the outer are little, if at all, 

 shorter than the earher and bear no dorsal processes, or at most a low blunt tubercle 

 at the distal end; surface of all the segments uniform in color and dull; no transition 

 segment; color plain (vol. 1, pt. 2, figs. 226-232, p. 180 and following; fig. 1347, 

 pi. 54) (Japan to the Kermadecs and westward to east and south Africa; Caribbean 

 Sea; sublittoral to abyssal) Charitometridae (pt. 4) . 



Suborder Oligophreata A. H. Clark 



Thalassomeiroida A. H. Cl.\rk, American Naturalist, vol. 42, No. 503, 1908, p. 722 (a new suborder; 

 triangular pinnules and small eggs). 



Comahilida Oligophreata A. H. Clark, Proc. Biol. Soc. Washington, vol. 22, 1909, p. 174 (includes 

 Comasteridae, Zygometridae, Himerometridae, Colobometridae, Thalassometridae, and Tro- 

 piometridae) ; Crinoids of the Indian Ocean, 1912, p. 43 (in key); Die Crinoiden der Antarktis, 

 1915, p. 110 (synonymy; diagnosis; geological, geographical, bathymetrical, and thermal ranges), 



Oligophreata A. H. Clark, Proc. U. S. Nat. Mus., vol. 40, 1911, p. 649 (includes Comasteridae. 

 Zygometridae, Himerometridae, Stephanometridae, Pontiometridae, Mariametridae, Colo- 

 bometridae, Thalassometridae, Calometridae, and Tropiometridae) . — A. H. Clark, Die Fauna 

 sudwest Australiens, vol. 3, Lief. 13, 1911, p. 438 (analysis of Australian species); Memoirs 

 Australian Mus., vol. 4, 1911, p. 717 (proportion of the species of this suborder in Australia as 

 known to P. H. Carpenter); p. 720 (representation in the Australian fauna); Crinoids of the 

 Indian Ocean, 1912, p. 6 (50 genera in the East Indian region; 280 species in the same region; 

 in other regions macrophreate species far outnumber the species of this suborder) ; in Springer 

 and Clark, Zittel-Eastman's Paleontology, 1913, p. 236 (diagnosis; includes nearly a dozen 

 different families); Bull, de I'Institut oc6anograpliique, Monaco, No. 294, 1914, p. 2 and follow- 

 ing (range; structural relation to terpperature) ; Journ. Washington Acad. Sci., vol. 4, No. 20, 

 1914, p. 581 (relation to temperature); Internat. Revue d. gesamt. Hydrobiol. u. Hydrogr., 



1914, p. 3 and follov,'ing (Atlantic and corresponding Indo-Pacific genera); Journ. Washington 

 Acad. Sci., vol. 5, No. 4, 1915, pp. 126-134 (bathymetrical range and its phylogenetic and 

 palaeontological significance); Die Crinoiden der Antarktis, 1915, p. 163 (all 4 crinoids known 

 from South Africa belong to 4 different families of this order) ; Amer. Journal of Science, vol. 40, 



1915, p. 67 (detailed discussion of bathymetrical range) ; Unstalked Crinoids of the Siboga Exped., 

 1918, p. 1; Smithsonian Miscell. Coll., vol. 72, No. 7, 1921, pp. 3, 12, 20, 21. 



