42 A Guide to the Zoological Collections 



Subclass TELEOSTOMI. 



Order I. TELEOSTEI [Cases 42-75]. 



In the Bony-fishes the skeleton is completely ossified 

 and the tail is homocercal : the gills are free, and lie, 

 on each side, in a gill-chamber, which is closed by a 

 gill-cover and opens to the exterior by a single gill-slit : 

 the bulbus arteriosus is non-contractile : the intestine 

 has no spiral valve : the optic nerves cross each other. 

 The skin is usually, but not always, scaly : the scales are 

 usually either cycloid or ctenoid, but bony scutes resem- 

 bling ganoid scales occur in some species, and granules 

 something like placoid scales are occasionally met with. 



Suborder AcANTHOPTERYGii [Cases 43-59] . 



The Bekti is a good type of this suborder. Some of 

 the dorsal, anal, and ventral fin-rays are spines. The 

 air-bladder, when it is present, rarely has a pneumatic 

 duct. 



There is really no hard and fast boundary line 

 between the Accuithoptcrygii and the Anacanthini and 

 Physostomi. 



The Indian species of Acanthopterygian Fishes are 

 grouped in 42 Families. 



Family I. Percidce [Cases 56-59]. 



The Perches are a large family to which about one- 

 tenth of all the Indian fishes at present known belong. 

 The Indian Perches are for the most part marine, a few 

 only — and those but small species — live exclusively in 

 fresh-water. The Bekti (Lates calcarifer) is the best 

 known of the many edible fishes of this family. 



There are 31 genera of Indian Perches, of which 

 three — namely C/ielidoperca, Synagrops and Brcphostoma 



