Classification of the Order Ostariopliysi. 565 



Family 10. Amphiliidae. 



Closely related to the Bagridae, but without pterygoid or 

 post-temporal. Air-bladder reduced and divided into two 

 lateral portions enclosed in incomplete bony cylinders formed 

 by the laminar parapophyses of the fourth vertebra, which 

 are decurved anteriorly, the rather feeble parapophyses of 

 the fifth vertebra, which do not nearly reach the skin, and by 

 two pairs of processes of the complex centrum supporting 

 the air-bladder below. Vertebrae 35 to 41 (16-20-1-18-21). 

 Anterior praecaudals with paired processes directed upwards 

 and outwards from the bases of the neural arches; para- 

 pophyses widely forked at the base. 



African fishes with depressed head, no nasal barbels, sub- 

 terminal or inferior mouth, toothless palate, and paired fins 

 horizontal and more or less expanded. In the structure of 

 the vertebral column they resemble the Indian Exostoma 

 and Pseudecheneis, and there are other interesting resem- 

 blances between members of this family and of the Sisoridae, 

 due to convergence. 



Synopsis of the Genera. 



I. Gill-membranes free from isthmus. All ribs on transverse pro- 



cesses ; caudal vertebrae normal. i^Ainphilihue.) 



Amphilins, Parmnphilius. 



II. Gill-membranes attached to isthmus. Anterior ribs sessile ; ver- 



tebrae behind dorsal fin with paired laminar processes directed 

 upwards and outwards, those behind the pelvic fins with similar 

 processes directed obliquely downwards, these processes reaching 

 the skin and often expanded distally to form series of bony plates. 



No bony plates Doumea, 



Series of bony plates from dorsal and pelvic 



fins to caudal Phractura, Paraphractura, 



Andersonia. 

 Lower series of bony plates continued for- 



waid in advance of pelvic fins Trachyglanis, Belonoglanis. 



Family 11. Chacids. (Fig. 2, D.) :/ 



The Indian genus Chaca appears to be related to the 

 Bagridae, from which it differs externally in the very large 

 strongly depressed head, the very wide mouth, the broad 

 union of the gill-membranes with the isthmus, and the exten- 

 sion forward of the caudal fin above and below, simulating 

 a second dorsal and anal. The large broad palatine articu- 

 lates with the strongly projecting lateral ethmoid and poste- 

 riorly with the metapterygoid ; there is no pterygoid, aud 



