714 BULLETIN 82, UNITED STATES NATIONAL MUSEUM VOLUME 1 



vol. 2, 1950, p. 134 (Danish record). HYMAN, The invertebrates, vol. 4, Echinodermata, 1955, 

 p. 113 (common in the Ingolf collections) . 



Hathrometra lenella MORTENSEN, Danmorfc-Expedition til Gr0nlands NE. kyst, vol. 5, No. 4, Medd. 

 Gr0nland, vol. 45, 1910, p. 243 (carries parasite Myzosloma carpenteri, here recorded from P. 

 prolixa), p. 246 (pentacrinoids compared with those of prolixa). GBFEG, Sci. Res. Michael Sarg 

 1910 Exped., 1921, p. 43 (notes). KOEHLEE, Les e'chinodermes des mers d'Europe, vol. 2, 1927, 

 p. 126 (in key), p. 128 (description; distribution). DJAKONOV, Les e'chinodermes des mers arc- 

 tiques, Leningrad, 1933, p. 25 (range) (in Russian). NOBRE, Echinodermes de Portugal, ed. 2, 

 1938, p. 189 (references; diagnosis). 



Hathromelra dentala MORTENSEN, Danmarfc-Expedition til Gr0nlands NE. kyst, vol. 5, No. 4, Medd. 

 Gr0nland, vol. 45, 1910, pp. 243, 245. GRIEG, Sci. Res. Michael Sars 1910 Exped., 1921, p. 43 

 (sta. 70; notes), p. 47 (listed). 



Hathrometra, sp. A. H. CLARK, Fisheries, Ireland, Sci. Invest., 1913, pt. 4, p. 2 (localities); Smith- 

 sonian Misc. Coll., vol. 61, No. 15, 1913, p. 71 (Porcupine stas. 51, 54). 



Hathrometra norvegica A. H. CLARK, Smithsonian Misc. Coll., vol. 61, No. 15, 1913, p. 63 (published 

 references to specimens in the British Museum; Triton sta. 5; Trondhjem Fjord, 150-300 fms.; 

 Norway, 800 fms.; Norway; size and number of cirrus segments given; no description) ; Unstalked 

 crinoids of the Sifcoffo-Exped., 1918, p. 246 (referable to Hathrometra). 



Antendon tenella GRIEG, Bergens Mus. Aarb., 1913, No. 1, p. 11 (notes). 



Hathromelra tenella var. sarsii GISLEN, Ark. Zool., vol. 15, No. 23, 1923, pp. 7-18, 25-30 (discussion; 

 localities; characters of specimens); Zool. Bidrag Uppsala, vol. 9, 1924, p. 28, footnote, pp. 68, 82 

 (articulations), p. 195 (development of cirri known), p. 205 (centrodorsal in development), p. 

 214 (extent of disk), p. 271 ; fig. 93, p. 87; figs. 114-115, p. 93; figs. 261-268, p. 199. MORTENSEN, 

 Danmarks Fauna, No. 27, 1924, p. 23; Handbook of the echinoderms of the British Isles, 1927, 

 p. 41. KOEHLER, Les e'chinodermes des mers d'Europe, vol. 2, 1927, p. 129. MORTENSEN and 

 LIEBERKIND, Die Tierwelt der Nord- und Ostsee, vol. 12, 1928, p. viii. 86 (food). ELIAS DA 

 COSTA, Chaves dicot6micas para a classifica$ao dos equinodermes Portugueses. No. 4, Crin6ides, 

 Porto, 1940, pp. 13, 15. GISLEN, Lunds Univ. Arsskr., new ser., Avd. 2, vol. 40, No. 8, 1944, 

 p. 80. 



Hathrometra sarsi MORTENSEN, Kungl. Norske Vid. Selsk. Skr., 1923, No. 3, 1924, p. 19 (Trondhjem 

 Fjord). KOEHLER, Les e'chinodermes des mers d'Europe, vol. 1, 1924, p. 60 (depth range). 

 MORTENSEN and LIEBERKIND, Die Tierwelt der Nord- und Ostsee, vol. 12, 1928, p. viii 3 (in 

 key), p. viii. 55 (whole North Atlantic), p. viii. 56 (range), fig. 2, 1, p. viii. 3 (cirrus), fig. 90, 

 p. viii. 51 (distribution). LIEBERKIND, Zoology of the Faroes, pt. 60, Echinoderma, 1929, p. 2 

 (Faroe references not justified; localities). MORTENSEN, Medd. Gr0nland, vol. 79, No. 2, 1932, 

 p. 50 (range). TORTONESE, Natura, Milano, vol. 24, 1933, p. 163 (depth range). DJAKONOV, 

 Journ. General Biol. Moscow, vol. 6, 1945, p. 131 (immigrant to N. Pacific from Atlantic). 

 TORTONESE, Bull. Inst. Octfanogr. Monaco, No. 956, 1949, p. 4 (bathymetrical range). HTMAN, 

 The invertebrates, vol. 4, Echinodermata, 1955, p. 113 (common in Ingolf collections). TORTON- 

 ESE, Ann. Mus. Civ. Stor. Nat. Geneva, vol. 68, 1956, p. 182 (Trondhjem; 80-150 meters). 



Hathrometra tenella norvegica KOEHLER, Les e'chinodermes des mers d'Europe, vol. 2, 1927, p. 129. 



Halhrometrea sarsi MORTENSEN and LIEBERKIND, Die Tierwelt der Nord- und Ostsee, vol. 12, 1928, 

 p. viii. 125 (host of parasite). 



Hathometra tenella RIVERA, Bol. Pesc. Madrid, vol. 14, 1929, p. 50 (in key). 



Harthrometra sarsi DJAKONOV, Les e'chinodermes des rners arctiques (in Russian), Leningrad, 1933, 

 p. 22 (in key), p. 25 (characters; range) ; fig. 12B, p. 25. 



Diagnostic features. This form seems to differ from //. tenella, of which it repre- 

 sents a northern and northeastern variety, only in being smaller with fewer cirrus 

 segments, which number from 14 to 24, and are usually about 20. 



Hathrometra sarsi has frequently been confused both with Poliometra prolixa and 

 with Heliometra glacialis. Some of the records for this species can only be explained 

 on the assumption that it has been confused also with species of Trichometra. 



From Poliometra prolixa, which resembles it in color and has P[ similarly elongated, 

 it is at once distinguished by the difference in the arrangement of the cirri on the 



