CHORD. \TA 



2S5 



bladder is present. The flesh of the sturgeons is eaten to a con- 

 siderable extent, and the eggs are made into caviare ; for this 

 purpose the eggs of the sterlet, a small species about a meter 

 in length, are considered the best. From the swimming bladder 

 isinglass is made. The shovel-nosed sturgeons, genus Scaphi- 

 rhynchus, have a flattened snout; one species occurs in the Mis- 

 sissippi and several others in Asia; it attains a length of about 

 a meter and a half, and lacks the spiracles of the common 

 sturgeon. 



The gar pikes and their allies have a well-ossified skeleton 

 and the surface of the body covered with enameled, rhombic 

 scales, closely approximated to one another ; these are called 

 ganoid scales. The mouth is terminal, and the jaws are pro- 

 vided with teeth ; in the common gar pike, Lepidostcus osscus 

 (Fig. 292), the jaws 

 are greatly elon- 

 gated. It has been 

 found only in 

 America and is 

 widely distributed 

 in the United States, 

 attaining a length 

 of a meter and a 



B 



jugpl 



hnlf The alli°ator ^"" 2C '3 - Amia calla - The bowfin or mudfish. A, entire 

 ^ animal; B, ventral side of head, br.m, branchiostegal mem- 



gar Of Olir Southern brane; c.f, caudal fin ; d.f, dorsal fin ; jug.pl, jugulai plate; 

 States grows to be ^-/Pectoral fin; ^./pelvic fin; "-/ventral ^fin. (After 



Gunther, from Parker and Haswell s I cxt-book.) 



twice as long. The 



spiral valve is very rudimentary, but the air bladder is highly 

 developed and assists in respiration, like the lungs of the higher 

 Vertebrata. The bowfin, Amia calva (Fig. 295), of the eastern 

 United States is somewhat closely related to the gar pikes. 



Order 2. Teleostei 



The Teleostei (Gr. Te\eo<$, complete, and dcrreov, bone) include 

 all the remaining fishes, except the three genera of the lungfishes 

 to be considered later. The group derives its name from the 

 skeleton, which is almost entirely of bone. In so large a group 

 as this the variation in external form is necessarily enormous, as 



