386 DESCRIPTIVE CATALOGUE OP AUSTRALIAN FISIIES, 



over the buccal aperture ; it is truncated in front, and this part 

 seen upperly, is rather bi-furcated. The lateral line is well 

 marked in all the length of the body ; there is only one dorsal, 

 which begins at about two-thirds of the length of the body, and 

 is joined with the caudal and anal fins ; the latter is considerably 

 shorter than the dorsal. No eye visible. The skin of the throat 

 is rather extensible ; the prolongation of the upper lip over the 

 lower is equal to the height of the body. The tail is pointed. 

 The colour is of a light green with the belly white, on the back 

 extends a narrow longitudinal line ; the head and throat are 

 pink, and the fins of the same colour/' 



Yarra Eiver (brackish water). Length four and three-eighth 

 inches. 



Sup-Class IV. LEPTOCARDII. 



Skeleton membrano-cwrtilaginom and notoclwrdal, ribless. JYo brain. 

 Pulsating sinuses in place of the Mart. Blood colourless. Respiratory 

 cavity confluent with the abdominal cavity; branchial clefts in great 

 ■number, the water being expelled by an opening in front of the vent. 

 Jaws none. 



Family CIEEOSTOMI, Owen. 

 Characters of the single genus. 



Genus Branciiiostoma, Costa. 



Body elongate, compressed, scaleless, limbless. Mouth a 

 longitudinal fissure, with sub-rigid cirri on each side, inferior. 

 Vent at a short distance from the extremity of the tail. A low 

 rayless fin-like fold runs along the back, round the tail, past the 

 vent to the respiratory aperture. Eye rudimentary. Liver 

 reduced to a blind sac of the simple intestine. 



Coasts uf temporate regiuns, imbedded in sand. 



