New and Rare Fossils. 47 



surface. The Australian specimen is short-spined and punctate. 

 and differs from 0. uinhonatum in the greater lengtli of the sliell 

 and the deeper median sulcus. 



Occur rence .—lioYe 8, 210-219 feet (Kalimnan or Janjukian). 



Cythekopteron phakantarcticum, sp. nov. (Plate IX., Figs. 39«, h). 



Description. — Valve, seen from the side, oblong, tapering to the 

 anterior, which is rounded, produced posteriorly. Margins sur- 

 rounded by a distinct rounded flange; dorsal strongly convex and 

 slightly sinuous, ventral nearly straight. Surface compressed 

 towards the dorsal margin, rising rapidly from the antero-dorsal 

 to the ventral side to form a prominent ala with a moderately 

 sharp point, but not hooked. The caudal extremity is sharp and 

 superficially rounded. Edge view of carapace, trapezoidal. Sur- 

 face of valve on the alar slope depressed in the median area, and 

 vellicate, marked by numerous fine punctations. 



Dimensions. — Length, .638 mm. ; height, to point of ala, .4 mm. ; 

 thickness of carapace, .73 mm. 



Affinities. — The relationship of the present species clearly lies 

 with the Antarctic species, C. antarcticum, recently found by me 

 in material from a raised beach (Pleistocene) S.E. of Mt. Larsen 

 (Shackleton Expedition, 1908). That species differs, however, in 

 the more attenuated carapace, and the sharply pointed but less 

 expanded alar process. Another species approaching the above 

 C. praeantarcticum is Cytheropteron hamatum, G. 0. Sars, which 

 differs essentially in the more depressed alae with their hooked 

 terminals. The latter is a North Atlantic and Arctic species, in 

 Pleistocene and recent deposits. 



Occurrence. — Bore 9, 256-263 feet (Kalimnan). 



Cytheropteron reticosum, sp. nov. (Plate IX , Fig.s. 40a, b) 



Description. — Carapace subquadrate, compressed. Seen from the 

 side, of nearly equal width from end to end ; anterior extremity 

 broadl}' rounded, posterior caudate; dorsal margin widely convex, 

 ventral nearly straight; a depressed flange runs round almost the 



1. Cytheropteron uespertilio, G. S. Brady, non Reuss, 1S68, Ann. and Mag. Nat. Hist., ser. 4, 

 vol. ii., p. 33, pi. v., figs. 6, 7. Cytheropttron hamatnm, G. O. Sar.s, 1869, Nye iJybvaiidserustaceer 

 fra Lofoten. Videt)s]£ Forhand., p. 172. 



