790 BULLETIN 82, UNITED STATES NATIONAL MUSEUM VOLUME 1 



Thermal range. One record, 8.89 C. 



Remarks. Of this species, which is much the largest and most robust of the genus, 

 only the 6 specimens above recorded have so far come to light. It is curious that all 

 of these are from Tokyo Bay. 



PENTAMETROCRINUS ATLANTICUS (Perrler) 



Eudiocrinus atlanticus PERKIER, Compt. Rend. Acad. Sci., vol. 96, No. 11, 1883, p. 725 (description; 

 Gulf of Gaseony, 896 m.; Travailleur) . P. H. CARPENTER, Challenger Reports, Narrative, vol. 1, 

 pt. 1, 1885, p. 310 (discussion). PERKIER, M<5moire sur 1'organisation et le developpement de la 

 comatule de la Mediterrane, 1886, p. 106 (sacculi) ; Explorations sous-marins, 1886, p. 275, fig. 

 195. P. H. CARPENTER, Challenger Reports, Zoology, vol. 26, pt. 60, 1888, pp. 4, 31, 74, 76-81, 

 369, 373, 374 (discussion). PERKIER, Traite" de zoologie, 1893, p. 858. MINCKERT, Arch. 

 Naturg., Jahrg. 71, vol. 1, Heft 1, 1905, p. 170, footnote (syzygies). HAMANN, Bronn's Klassen 

 und Ordnungen des Tier-Reichs, vol. 2, Abt. 3, 1907, p. 1576 (listed). A. H. CLARK, Proc. U.S. 

 Nat. Mus., vol. 32, 1907, p. 573 (first reference; type locality) ; vol. 34, 1908, p. 271 (history) ; vol. 

 35, 1908, pp. 113, 114 (arm structure). KOEHLER, Resultats des Campagnes scientifiques 

 accomplies sur son yacht par Albert 1", Prince souverain de Monaco, fasc. 34, 1909, p. 271 

 (Princesse- Alice stas. 486, 1894; 578, 1895; 1118, 1901), pi. 32, figs. 15-18. VANET, Bull. Mus. 

 Hist. Nat., Paris, No. 3, 1910, p. 160 (relation to Decamelrocrinus of the species of Eudiocrinus 

 typified by this form) . 



Comatule PARFAIT, Rapport sur la campagne scientifique du Talisman en 1883, 1884, p. 45 (3227 

 N., 1215' E.; 1123 m.; June 17, 1883). DE FOLIN, Sous les mers, 1887, p. 277 (same record) . 



Eudiocrinus, sp. KOEHLER, Ann. Univ. Lyon, vol. 26, June 1896, p. 101 (Caudan sta. 11; "without 

 doubt E. atlanticus"}. 



Pentametrocrinus atlanticus A. H. CLARK, Proc. Biol. Soc. Washington, vol. 21, 1908, p. 135 (listed); 

 Proc. U.S. Nat. Mus., vol. 34, 1908, p. 277 (listed) ; vol. 35, 1908, p. 117 (arm structure); vol. 40, 

 1911, p. 7 (northwest coast of Africa), p. 7, footnote (also West Indies), p. 9 (indicates a West 

 Indian element in the northwest African fauna), p. 44 (synonymy; localities and range); Bull. 

 Mus. Hist. Nat., Paris, No. 4, 1911, p. 245 ( = Eudiocrinus allanlicus), p. 259 (Talisman sta. 45); 

 Fisheries, Ireland, Sci. Invest., 1913, pt. 4, p. 4 (Helga stations; notes); Unstalked crinoids of the 

 Siboj/a-Exped., 1918, p. 261 (in key; range); The Danish Ingolf-'Exped., vol. 4, No. 5, Crinoidea, 

 1923, p. 44 (range). GISLEN, Zool. Bidrag Uppsala, vol. 9, 1924, pp. 26 and following (articula- 

 tions). MORTENSEN, Handbook of the echinoderms of the British Isles, 1927, p. 24 (diagnosis; 

 records) ; fig. 11, p. 24 (from Perrier). GISLEN, Ark. Zool., vol. 19, No. 32, 1928, p. 12 (notes). 



Eudiocrinus (Pentametrocrinus) atlanticus KOEHLER and VANET, Bull. Mus. Hist. Nat., Paris, No. 1, 

 1910, p. 26, p. 31 (localities). 



Pentametrocrinus (Eudiocrinus) atlanticus KOEHLER, Les e'chinodermes des mers d'Europe, vol. 2, 

 1927, p. 133 (listed). 



Diagnostic features. Closely resembling P. diomedeae, but more slender and less 

 robust with the centrodorsal flattened hemispherical to low conical and bearing 

 XX-XXXV cirri which are slightly longer, reaching a quarter or more of the arm length; 

 the perisome of the disk and arm bases is thickly beset with conspicuous, though very 

 small, calcareous plates; the proximal pinnules have about 15 segments. 



Description. The centrodorsal is small, hemispherical, or flattened hemispherical, 

 with the cirrus sockets arranged in about two marginal rows. 



The cirri are XX-XXXV, with 14 to 17 segments and reaching a maximum of 

 35 mm. in length. The first two segments are very short, a little broader than long, but 

 the segments that follow rapidly become more elongated, the fourth being 3 tunes 

 as long as broad, and the fifth and sixth 3 or 4 times as long as broad. From this 

 point onward the length of the segments gradually decreases to the penultimate, which 

 is slightly longer than broad. The terminal claw is gently curved. Below the periphery 

 of the centrodorsal the cirri are shorter, with 11 to 12 segments. 



