550 BULLETIN 82, UNITED STATES NATIONAL MUSEUM VOLUME I 



Localities. Discovery Investigations station 160; near Shag Rocks (lat. 5343'40" 

 S., long. 4057' W.); 177 meters; bottom gray mud, stones and rock; February 7, 1927 

 [John, 1938] (1, B.M.). Type locality. 



B.A.N.Z.A.R.E. station 41; off Enderby Land (lat. 6548' S., long. 5316' E.); 

 200 meters; bottom temperature 1.77 C., salinity 34.24% ; January 24, 1930 [John, 

 1939] (1, B.M.). 



B.A.N.Z.A.R.E. station 42; off Enderby Land Gat. 6550' S., long. 5423' E.); 

 220 meters; January 26, 1930 [John, 1939] (1, B.M.). 



History. Eumorphometra aurora was described by Dr. D. Dilwyn John in 1938 

 from a single specimen dredged by the Discovery in 1927. In 1939 the same author was 

 able to amplify his description and to show, from two further specimens taken by the 

 B.A.N.Z.A.R. Expedition in 1930, that the species is viviparous. 



Geographical range. Shag Rocks area (53 S., 40 W.) and off Enderby Land 

 (66 S., 53 E.). 



Bathymetrical range. From 177-220 meters. 



Thermal range. The single record is of 1.77 C. 



Salinity range. The single record is 34.24% . 



Genus HYBOMETRA A. H. Clark 



Hybomelra A. H. CLARK, Smithsonian Misc. Coll., vol. 61, No. 15, 1913, p. 54 (diagnosis; type species 

 H. senta); Journ. Washington Acad. Sci., vol. 7, 1917, No. 5, p. 127 (referred to the Antedoninae) ; 

 No. 16, p. 506 (in key; range); Unstalked crinoids of the Siboga-Exped., 1918, p. 198 (in key; 

 range), p. 217; Univ. Iowa, Studies in Nat. Hist., vol. 9, No. 5, 1921, p. 12 (confined to the West 

 Indian region), p. 17 (in key); The Danish Ingolf-Exped., vol. 4, No. 5, Crinoidea, 1923, p. 41 

 (range), p. 52 (in key); Mem. Soc. Cubana Hist. Nat., vol. 14, No. 2, 1940, p. 139. 



Diagnosis. A genus of Zenometrinae in which the centrodorsal is conical but not 

 quite as high as wide; the cirrus sockets are in 20 columns but are not separated into 

 radial groups; interradial columns are of four sockets each but the radial ones are 

 abbreviated towards the apex and are slightly irregular; the cirri are unknown, also 

 PI; P 2 is very long and attenuate with about 27 segments; P 3 is much shorter, just over 

 half as long as P 2 , with 14 to 15 segments; the division series are slightly spinous and 

 this increases on the distal brachials. 



Type species. Hybometra senta A. H. Clark, 1913. 



Geographical range. Only known from the coast of Brazil. 



Bathymetrical range. Only known from 42 meters. 



HYBOMETRA SENTA A. H. Clark 



FIGURE 31 



Hybometra senta A. H. CLARK, Smithsonian Misc. Coll., vol. 61, No. 15, 1913, p. 54 (description; 

 locality); Unstalked crinoids of the Siboga-Exped., 1918, p. 217 (references); The Danish 

 Ingolf-Exped., vol. 4, No. 5, 1923, Crinoidea, p. 41 (range) ; Mem. Soc. Cubana Hist. Nat. 

 vol. 14, No. 2, 1940, p. 140 (in key), p. 144 (reference). 



Description [by A.M.C.]. The centrodorsal is conical, 3.2 mm. in vertical height 

 or 3.6 mm. from the apex to the interradial border and 4.1 mm. in basal diameter. 

 There are about LXVI cirrus sockets of which 20 are peripheral, four corresponding to 

 each radial area. The two outside ones in each area form the bases of regular columns 

 of four sockets, which converge to meet near the apex of the centrodorsal. In the 



