OF GREAT BRITAIN. 85 



teeth on each side. Upper jaw somewhat duck-billed. Teeth 

 on vomer small ; on the palatine bones larger and longer, parti- 

 cularly on the inner edges : none on superior maxillary bones. 

 Head covered with mucous orifices placed in pairs. Cheeks 

 and upper parts of gill-covers covered with scales. Colour of 

 head and upper part of back dusky olive-brown, growing lighter 

 and mottled with green and yellow on sides, passing into silvery 

 white on belly ; pectoral and ventral fins pale brown ; back-, 

 anal-, and tail-fins darker brown, mottled with white, yellow, and 

 dark green. 



