146 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



Endiocrinus BATHER, Kept. Brit. Assoc. for 1898, 1899, p. 923. CHUN, Aus den Tiefen des Welt- 



meeres, 1900, p. 488. HTTTTON, Index faunae Novae Zelandiae, 1904, p. 291. 

 Eudiocrinis A. H. CLARK, Smithsonian Misc. Coll., vol. 60, No. 10, 1912, p. 12. 

 Eudiocri-uus, GISL^N, Nova Acta Reg. Soc. Sci. Upsaliensis, ser. 4, vol. 5, No. 6, 1922, p. 182. 



Diagnosis. A genus of comatulids with five arms only ; IBr series are present in 

 which the two elements are united by syzygy and the distal bears a pinnule instead of 

 being axillary. 



This is the only genus in the family Eudiocrinidae; for further information re- 

 garding its characters and relationships see page 143. 



Geographical range. From the Maldive Islands, Cape Negrais, Burma, and the 

 Andaman Islands to the Lesser Sunda and Kei Islands, the Moluccas, the Philippine 

 and Bonin Islands, and southern Japan. 



Bathymetrical range. From 36 to 183 meters. 



Remarks. While the genus Eudiocrinus is one of the most clearly delimited and 

 most definitely characterized of all comatulid genera the interrelationships of the in- 

 cluded species are as yet by no means entirely clear. 



The curious elongated cirri of E. junceus seem to be quite distinctive, differentiat- 

 ing that species sharply from all the others. But as it has only been taken once we 

 know nothing of its geographical or other variations. 



Similarly the short and strongly recurved cirri composed of short segments charac- 

 teristic of E. variegalus, E. loveni, and E. pinnatus seem to indicate that these species 

 form a natural group. But these species are very insufficiently known, while the 

 cirri in certain individuals of other species sometimes approach the short-segmented 

 type rather closely. 



The small and slender E. venustulus appears to be a well-marked form, although it 

 is sometimes rather easily confused with the young of the larger and stouter species. 



Though on the basis of our present information E. gracilis, E. pulchellus, and E. 

 eoa appear to be quite distinctive, as yet we know very little about them. 



Whether E. ornatus, E. philenor, and E. serripinna are to be regarded as species 

 or as forms of E. indivisus is more or less a matter of personal opinion. The inter- 

 relationships of serripinna, ornatus, and indivisus are extraordinarily similar to the 

 interrelationships between Oligometra serripinna and its corresponding varieties. 



History. In 1868 Prof. Carl Semper established the genus Ophiocrinus for the 

 reception of a curious little comatulid that he called Ophiocrinus indivisus from the 

 Philippine Islands. In the following year a second species was described by Prof. 

 Percival de Loriol under the name of Comatula (Ophiocrinus} hyselyi from the Neo- 

 comian of Switzerland. 



The generic value of the character separating Ophiocrinus from Antedon or 

 Comatula, as those genera were understood at that time, was doubted by Schliiter in 

 1878, and P. H. Carpenter had some hesitation in regarding it as equivalent to Antedon, 

 Actinometra, and Promachocrinus. 



The Challenger had dredged three species of 5-armed comatulids in the western 

 Pacific, and in 1882 Carpenter described these, at the same time red escribing Semper's 

 Ophiocrinus indivisus, the type and only specimen of which had been acquired by his 

 father. Carpenter pointed out that the generic name Ophiocrinus had been used by 

 Salter in 1853 and was not therefore available for Semper's genus, for which he pro- 



