776 " THKTIS " SCIENTIFIC RESULTS. 



Specimens in the Australian Museum Collection. — Port Curtis, 

 Queensland — ^Three s])ecimens. 



Additional Aust7'alian Records. — Port Curtis, in 7 fathoms, 

 and in 11 fathoms; Prince of Wales Channel, in 7-9 fathoms; 

 Bassett-Smith Bauk, in 9 fathoms ; Holothuiia Bank, in 39 

 fathoms; Baudin Island, in 8-15 fathoms. 



OLIGOMETRA ADEON^ {Lamarck). 



Comatula adeonce, 1816, Lamarck, Hist. Nat. des animaux sans 

 vertebres, vol. 2, p. 535 (Australia). 



Antedon adeonoi (part), 1884, Bell, Rep. Zool Coll. H.M.S. 

 "Alert, p. 156 {Fort Curtis; Port Denison). 



Antedon pinnif or mis, 1884, Bell, loc. cit. {Dundas Strait). 



Antedon bidens, 1884, Bell, Rep. Zool. Coll. H.M.S. "Alert," 

 p. 158, pi. xi., figs. Aa-c (Torrks Strait). — 1898, Doderlein, 

 Denkschr. Ges. Jena, vol. 8, p. 476, pi. 36, figs 3-3d {Thurs- 

 day Island). 



Oligometra bidens, 1908, A. H. Clark, Proc. Biol. Soc. Washing- 

 ton, vol. 21, p. 126.— 1909, A. H. Clark, ZooL Anzeiger, 

 vol. 34, p. 368 {N. W. Australia). 



Oligometra adeonce, 1908, A. H. Clark, Proc. Biol. Soc. Wash- 

 ington, vol. 21, p. 126. 



Differential Characters. — This species is related to 0. thetidia, 

 and these two are easily distinguished from the other Australian 

 species of the genus by the large size of P^ and the compara- 

 tively small size and smoothness of Pg, as well as by their stout, 

 robust build. The cirrus segments of 0. bidens bear dorsally 

 double transverse ridges instead of a single transverse ridge as in 

 0. thetidis, and are more numerous ; the genital pinnules of 0. 

 bidens do not appear to be expanded laterally as in 0. thetidis. 



Australian Records. — "Australia"; Torres Strait, in 10 fathoms ; 

 Thursday Island ; Port Curtis ; Port Denison ; Dundas Strait : 

 Baudin Island, in 8-15 fathoms; North-western Australia. 



Remarks. — At Paris I examined the types of this species, 

 which vi^ere obtained in Australia by MM. Peron and Le Sueur 

 in 1803 ; the cirri are about xxx, 17-20 (most commonly 19), 

 very stout ; the first segment is very short, the following gradu- 

 ally increasing in length and becoming nearly as long as broad 

 on the sixth and following ; the fourth and following have on 

 the dorsal surface two transverse ridges which appear as two 

 small spines in lateral view 



The rays and first three brachials resemble these of the species 

 of Trojnometra in being very broad and sharply flattened against 



