A MONOGRAPH OF THE EXISTING CRINOIDS 175 



tion before the description of E. minor, which accounts for the appearance of Eudio- 

 crinus ornatus, a new name, without any explanation in the description of E. minor. 



In 1912 both Eudiocrinus ornatus and E. minor were redescribed and figured. 

 Of E. ornatus there were recorded six specimens from the type locality and one from 

 another locality in the Andamans, while of E. minor the type was the only specimen 

 mentioned. 



In 1918 Eudiocrinus minor was placed, without explanation, in the synonym of 

 E. ornatus. The name ornatus was used in preference to minor for the reason that it 

 is based upon a fully developed individual with all its characters developed, whereas 

 the name minor is based upon a small and young specimen concerning the exact 

 determination of which it is possible to entertain a certain amount of doubt. 



Technically the mention of the overlapping of the brachials and pinnulars of E. 

 ornatus in the comparison with E. minor may be considered as an "indication" of 

 its characters as that term is used in nomenclature, and therefore the names minor 

 and ornatus may be regarded as of the same date. 



In 1918 two specimens were recorded from Siboga station 294. 



In 1932 I recorded and gave notes upon a specimen from Investigator station 387. 



EUDIOCRINUS GRACILIS A. H. Clark 



Plate 12, Figure 48 

 [See also vol. 1, pt. 2, fig. 189 (side view), p. 109.] 



Eudiocrinus gracilis A. H. Clark, Crinoids of the Indian Ocean, 1912, p. 315 (description; Investi- 

 gator station 387); Unstalked crinoids of the Siboga-Exped., 1918, p. 65 (in key; range). — 

 Gislen, Nova Acta Reg. Soc. Sci. Upsaliensis, ser. 4, vol. 5, No. 6, 1922, p. 7 (Burma; also 

 represented by a somewhat divergent form [pulchellus] in the Bonin Islands), p. 72 (compared 

 with E. g. var. pulchellus). — A. H. Clark, Temminckia, vol. 1, 193G, p. 295 Clisted), p. 301 

 (Suvadiva Atoll; notes); John Murray Exped. 1933-34, Sci. Reports, vol. 4, No. 4, 1936, p. 99 

 (range), p. 103. 



Diagnostic features. — In general resembling E. indivisus, but P a and P 2 are about 

 twice as long as P c and Pi, relatively slender, with much elongated segments of which 

 the third is half again as long as broad and the distal are about three times as long as 

 broad. 



Description. — The centrodorsal resembles that of E. indivisus. 



The cirri are X, 15-16, 9 mm. long. The first segment is about three times as 

 broad as long, the second is about twice as broad as long, the third is about as long as 

 the width of its expanded distal end, and the fourth and fifth are about twice as long as 

 their proximal width, the fifth being slightly longer than the fourth. The following 

 segments are about as long as their distal width. The cirri taper gradually to the 

 fifth segment, which is a well marked transition segment, and are more delicate from 

 that point onward. The longer earlier segments are strongly constricted centrally 

 with prominent flaring distal ends. Beyond the fifth segment the ventral profile 

 becomes straight, but the distal dorsal edge is produced so that the dorsal profile of 

 the cirrus as a whole is strongly serrate. The antepenultimate segment is slightly 

 longer than broad, without any production of the distal dorsal edge. The penul- 

 timate segment is wedge-shaped, about as long as the greater (ventral) length. The 

 opposing spine is prominent, arising from the entire dorsal surface of the penultimate 



