A MONOGRAPH OF THE EXISTING CRLNOIDS 6 



October 26, 1933, p. 483. A. H. CLARK, Treuhia, vol. 14, livr. 2, December 1933, p. 213. 

 GISLN, Kungl. Fysiogr. Sallsk. Handl., new ser., vol. 45, No. 11, 1934, pp. 18, 20, 22, 23, 25, 

 27, 28, 43. A. H. CLABK, Temminckia, vol. 1, 1936, p. 313; John Murray Expcd. 1933-34, 

 Sci. Reports, vol 4, No. 4, 1936 (Jan. 1, 1937), pp. 92, 101, 103. GISLN, Kungl. Svenska Vet. 

 Handl., ser. 3, vol. 17, No. 2, Oct. 3, 1938, pp. 4, 17. NOBRE, Echinodermes de Portugal, 1938, 

 p. 185. H. L. CLARK, Mem. Soc. Cubana Hist. Nat., vol. 15, No. 1, May 1941, p. 8. A. H. 

 CLABK, Bernice P. Bishop Mus. Bull. 195, 1949, p. 74. 



Thalassometridae with rounded and spiny rays and arm bases A. H. CLARK, Amer. Nat., vol. 42, 

 No. 500, 1908, p. 542 (characteristic of Oceanic area); Geogr. Journ., vol. 32, No. 6, 1908, p. 602 

 (same) ; Proc. U. S. Nat. Mus., vol. 36, 1909, p. 495 (comparison of ambulacra! plating with that 

 of West Indian species of the Fimbriata group of Actinometra) . 



Thalassometrinae A. H. CLARK, Proc. Biol. Soc. Washington, vol. 22, 1909, p. 2 (diagnosis and com- 

 parisons), p. 13 (revision of included genera); Vid. Medd. Naturh. Foren. K0benhavn, 1909, p. 

 124 (multibrachiate condition fortuitous in most species), p. 136 (transition segment in cirri 

 comparable to that in Comafella slelligera), p. 151 (transition segment comparable with that of 

 Zygomelra fluctuant [^comala]); Mem. Australian Mus., vol. 4, 1911, p. 728 (raised to family 

 rank). HARTLATJB, Mem. Mus. Comp. Zool., vol. 27, No. 4, 1912, p. 286 (discussion). A. H. 

 CLARK, Bull. Inst. Ocdanogr. Monaco, No. 294, 1914, pp. 7, 8 (temperature relations); Journ. 

 Washington Acad. Sci., vol. 4, No. 19, 1914, pp. 559-563 (correlation of geographical and bathy- 

 metrical ranges); No. 20, 1914, p. 582 (relation to temperature of habitat); vol. 5, No. 4, 1915, 

 pp. 126-134 (pnylogenetical and paleontological significance of the bathymetrical range); 

 Amer. Journ. Sci., vol. 40, 1915, p. 67 (detailed discussion of bathymetrical range); 

 Unstalked crinoids of the Siboga-Exped., 1918, p. 140 (in key; geographical and bathymetrical 

 ranges), p. 145 (key to the included genera); Smithsonian Misc. Coll., vol. 72, No. 7, 1921, pp. 

 3, 13. GISLN, Zool. Bidrag Uppsala, vol. 9, 1924, pp. 85, 90. BOONE, Bull. Biugham Ocean- 

 ographic Collection, vol. 1, art. 4, April 1928, p. 3. A. H. CLARK, Journ. Linn. Soc. (Zool.), 

 vol. 36, No. 249, April 1929, p. 647; Ann. Mag. Nat. Hist., ser. 10, vol. 10, No. 58, October 

 1932, p. 379; Rec. Indian Mus., vol. 34, pt. 4, December 1932, p. 565. 



Thalassometres A. H. CLARK, Bull. Mus. Hist. Nat., Paris, No. 4, 1911, p. 255 (including Plilometra, 

 taken from the Tropiometridae). 



Thalassometriden A. H. CLARK, Die Crinoiden der Antarktis, 1915, p. 192 (species and genera of 

 this family especially characteristic of the Intermediate fauna). 



Diagnosis. A family of the superfamily Tropiometrida in which the ventral 

 perisome of the pinnules is protected by well-developed and conspicuous side- and 

 covering-plates easily visible with a hand lens; PI is longer and stouter than P^; and the 

 cirri, usually long and slender, rarely of moderate length and rather stout, are composed 

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

 mal, broader than long, with prominent dorsal spines or carinate processes; a well- 

 marked transition segment is usually present, beyond which the segments have the 

 surface light in color and highly polished. 



Geographical range. From southern Japan, the western Aleutian Islands, the 

 Hawaiian Islands, the Galapagos Islands, and PanamA to the Kermadec Islands and 

 southeastern Australia (Bass Strait) westward to the east coast of Africa and the 

 Crozet Islands, and in the Atlantic from Tristan da Cunha and Ascension northward 

 to the Bay of Biscay, the Caribbean Sea, and the Bahamas. 



Bathymetrical range. From 22 to 2,925 meters. 



Thermal range. From 1.2 to 23.6 C. 



Remarks. The species of the family Thalassometridae, though diversified, are 

 quite distinctive, the stiff pinnules with well developed side- and covering-plates, the 

 enlarged PI, which is always larger and often much longer than P 3 , and the usually long 

 and slender cirri which bear dorsal spines in the outer portion, making them easy to 



