SAUROID FISHES. 209 



combines in the structure both of the bones, and some of 

 the soft parts, characters which are common to the class 

 of reptiles. M. Agassiz has already ascertained seventeen 

 genera of Sauroid Fishes. Their only living representa- 

 tives are the genus Lepidosteus,* or bony Pike (PI. 27* Fig. 

 1.) and the genus Polypterus (Agass. Poiss. Foss. Vol. 2. 

 Tab. C.) the former containing five species, and the latter 

 two. Both these genera are found only in fresh-waters, 

 the Lepidosteus in the rivers of North America, and the 

 Polypterus in the Nile, and the waters of Senegal.f 



The teeth of the Sauroid Fishes are striated longitudi- 

 nally towards the base, and have a hollow cone within. 

 (See PI. 27% 2, 3, 4; and PI. 27. 9, 10, 11, 12, 13,14.) The 

 bones of the palate also are furnished with a large appa- 

 ratus of teeth .J 



PI. 27, Figs. 11, 12, 13, 14, represent teeth of the largest 

 Sauroid Fishes yet discovered, equalling in size the teeth 

 of the largest Crocodiles : they occur in the lower region 

 of the coal formation near Edinburgh, and are referred by 

 M. Agassiz to a new genus, Megalichthys. PI. 27, Fig. 9, 

 and PI. 27% Fig. 4, are fragments of jaws, containing many 



* Lepidosteus Agassiz — Lepisosteus Lacepede. 



t The bones of the skull, in Sauroid Fishes, are united by closer sutures 

 than those of common Fishes. The vertebriB articulate with the spinous 

 processes by sutures, like the vertebrce of Saurians ; the ribs also articulate 

 with the extremities of the transverse processes. The caudal vertebrae have 

 distinct chevron bones, and the general condition of the skeleton is stronger 

 and more solid than in other Fishes : the air-bladder also is bifid and cellu- 

 lar, approacliing to the character of lungs, and in the throat there is a glot- 

 tis, as in Sirens and Salamanders, and many Saurians, — See Report of Pro- 

 ceedings of Zool. Soc. London, October, 1834. 



t The object of the extensive apparatus of teeth, over the Whole interior of 

 the mouth of many of the most voracious Fishes, appears not to be for mas- 

 tication, but to enable them to hold fast, and swallow the slippery bodies of 

 •ther Fishes that form their prey. No one who has handled a living Troat 

 or Eel can fail to appreciate duly the importance of the apparatus in que?,. 

 Uon. 



18* 



