BOW-FINS. 79 



bubbles of gas from the nostrils, situated near the end of the 

 snout, in a manner suggesting that the air-bladder assists in the 

 respiration. 



Amiiformes (Bow-fins). 



The Amiiformes or Protospondyli form a suborder of fishes Wall- 

 all of which, except Amia, the Bow-fin of North America, are 

 extinct, and most of which are Mesozoic in their stratigraphical 

 range. The dermal fin-rays of the dorsal and anal fins are equal 

 in number to the endoskeletal supporting elements; the endo- 

 skeletal elements of the pelvic fins are rudimentary or absent ; 

 there is no infraclavicle in the pectoral girdle. The extremity of 

 the vertebral column is upturned, but the outline of the tail-fin is 

 symmetrical. There is a median jugular plate between the halves 

 of the mandible; the branchiostegal rays are flattened and rather 

 broad; in the mandible are splenial and coronoid bones; there 

 are two vomerine bones (coalescent in the Pycnodontidse) ; there 

 is no supraoccipital bone (except in Dapedius). The suborder 

 comprises the families Semionotidse, Macrosemiidse, Pycnodontidse, 

 Eugnathidse, Amiidae, aud Pachycormidse. 



Fig. 46. — Lepidotus mantelli. 



The Semionotidse (fig. 46), the oldest and most generalised of Le F~ 

 the Amiiformes, are represented by Lepidotus notopterus (222), 

 from the Lithographic Stone of Bavaria, the great Lepidotus 

 maximus (1037, Table 49) from the same formation and locality, 

 and a specimen of Dapedius leiosomus (223). In this family 



