300 THE FAMILY AMPHIPNOID^ GILL. 



The characteristics of the Amphipnoidoi as a family are as follows : 



AMPHIPNOIDiE. 



Synont/ms as family names. 



= Pneuraobranchoidei Bleeker, Enum. sp. Piscium Archipel. Ind., p. xxxii, 1856. 



:= Amphipuoidpe GUI, Arrangemeut Fam. Fishes, p. '20, 1872. 



= Aniphipnoidse Gill, Standard Nat. Hist., v. 3, p. 100, 1885. 



Anguilliformes sp. Olivier et al. 



Mur.-Buidae gen. Bonnp. 



Sphagebranchidtu gen. Richardson (1845). 



Anguillares gen. Midler (olim). 



Syubranchidse geu. Swainson, MiiUer, et al. 



Synonyms as suhfamily names. 



= Pueumobraucbiui Blrcl-er, Atlas Icb. Iiides Neerland, t. iv, p. 117, 1864. 

 = Aiupbipuoiua Giinther, Cat. Fishes. B. M., v. 8, p. 12, 1870. 



DIAGNOSIS. 



Holoston.ous Symbranchians peculiar iu the development of a pair 

 of bladders behind the head (one on each side of the nape) receiving a 

 portion of the blood from the branchial artery and with the branchiae 

 reduced (to laminae on the second branchial arch). 



DESCRIPTION. 



Body anguilliform, anteriorly subcylindrical, behind compressed, 

 -especially in the caudal portion ; with the anus far behind in the termi- 

 nal fourth of the length. 



Scales minute, arranged in longitudinal rows. 



Lateral line distinct, arched forwards, straight behind. 



Read small, ovate-conical, without external prominences. 



Eyes within the anterior fourth of the head, directed mostly sideways, 

 of small size. 



Nostrils mostly superior ; the posterior above the orbit and provided 

 with a valve, the anterior advanced forward on the snout and subcir- 

 cular. 



Jaics well developed; the intermaxillines and supramaxillines con- 

 nected immovably with each other and with the front of the cranium; 

 intermaxillines with a rather broad surface and with projecting proc- 

 esses in front ; supramaxillines appressed to the upper surface of the 

 intermaxillines forwards and curved upwards and backwards and ex- 

 panded vertically downwards behind. Mandible stout ; dentary difter- 

 entiated by its hard compact structure, with its external surface deeply 

 incised for the articular and with its terminal portion expanded up- 

 wards into a broad high coronoid process ; articular long, with a wide 

 cotyloid cavity separated by a considerable interval from the dentary, 

 with an attenuated portion applied to the inner surface of the dentary 

 and fitting into the deep notch of the external wall of the dentary ; 



