BY J. DOUGLAS OGILBY. 41 



posterior to this and in a line with it is a long ridge ending in a 

 spine on the j)terotic ; the supraoccipital has a low, irregular, 

 Y-shaped ridge in its middle line, and the parietal has a pro- 

 minent spine just external to this; the epiotic is like a scale on 

 the greatly develoj)ed opisthotic, and ends in a sharp point, which 

 does not stand out like a spine; opisthotic greatly produced 

 posteriorly, terminating in a prominent spine. 



ATHERINID^. 



T^NiOMEMBRAS, gen.nov. 



Body elongate and compressed, the abdomen rounded, covered 

 with moderate, adherent, cycloid scales. Head small, a little 

 deeper than wide, with moderate, pointed snout, partially scaly, 

 the snout, interorbital region, and preopercular border naked and 

 provided with series of large open pores. Mouth terminal, small, 

 with oblique cleft; jaws subequal, with the edges nearly linear. 

 Premaxillaries narrow throughout, pi'otractile, the skin not con- 

 tinuous with that of the forehead ; maxillary almost entirely 

 concealed beneath the preorbital, not extending backwards to the 

 eye. Upper jaw with several, lower with a single series of small, 

 conical teeth; palatine teeth uniserial, strong; vomer, pterygoids, 

 and tongue smooth. Eyes lateral, without adipose lid. Six 

 branchiostegals; gill-rakers short and stout. Two widely separated 

 dorsal fins, with vi-viii, i 9-11 rays, the spinous ones flexible 

 anal originating l^elow the dorsal interspace, with i 10-12 rays; 

 ventrals small, well separated, with a feeble spine and 5 soft rays, 

 without intermediate scaly process; pectorals high, with 12-14 

 rays, the upper the longest; caudal forked, the peduncle slender. 

 "Vent situated below the first dorsal. Vertebrae 42. 



Etymology: — raivios, slender; Memhras, a related genus = 

 Ailierina. 



Type: — Atlierina microstoma, Giinther. 



Distribution : — Atherinids from the fresh and brackish 

 waters of Tasmania, allied to Atlierina, but differing in the more 

 elongate body, pointed snout, small mouth, stronger dentition, 

 shorter, stouter and fewer gill-rakers, kc. 



