GANOIDEI. 367 



Gyrodus, 3Icsturus, Microdon, Cododus, Pycnodus, Mcsodon, are 

 some of the genera distinguislied by palceontologists. (See 

 Fig. 102, p. 201.) 



SEVENTH SUB-OEDEE— LEPIDOSTEOIDEI. 



Scales ganoid, rhombic ; fins generally with fulcra; paired 

 fins not lohate. Free- and inter- operculum developed; generally 

 mimerous hranchiostcgcds, hid no gular plate. 



First Fa:\iily — LEPiDosxEiDyE. 



Sccdes ganoid, lozenge-shaped. Skeleton completely ossified ; 

 vertehrce convex in front and concave behind. Fins tvith fulcra ; 

 dorsal and ancd composed of articulated rays only, placed far 

 backivards, close to the caudal. Abdominal part of the vertebral 

 column much longer than caudcd. Branchiostegals not mcme7'- 

 ous, without enamelled surface. Heterocerccd. 



Lepiclosteus. — Body elongate, sub-cylindrical ; snout elongate, 

 spatulate, or beak-shaped ; cleft of the mouth wide ; both jaws 

 and palate armed with bands of rasp -like teeth and series of 

 larger conical teeth. Four gills ; no spiracles ; three branchio- 

 stegals. Air-bladder cellular, communicating with the pharynx. 



Fig. 145. — Lepiclosteus viridis. 



Fishes of this genus existed already in Tertiary times ; 

 their remains have been found in Europe as well as North 

 America. In our period they are limited to the temperate 

 parts of North America, Central America, and Cuba. Three 

 species can be distinguished which attain to a length of about 

 six feet. They feed on other fishes, and their general resem- 

 blance to a pike has given to them the vernacular names of 

 " Gar-Pike," or " Bony Pike." 



