262 PHILOSOPHY OF ZOOLOGY. 



With a hind toe. 



215. CoLYMBus. Diver. Claws pointed. C. gacialis. 

 M. CuviER has brought together the Immer as a variety of 

 glacialisy probably with propriety, but he errs in associat- 

 ing with it the ai'cticus also. This last is the male of the sep- 

 ientrionalis. C stellatus, which Cuvier makes a var. of 

 septentrionalis, is a true species. The bill alone is sufficient 

 to mark the difference. 



Without a hind toe. 



Upper mandible notched at the extremity. 



216. Uria. Guillemot. The Colymbus Troile, is the 

 representative of this genus *. When in its winter dress, 

 or ifhrnature state, it is the C. minor of authors. Monta- 

 gu states, that this last is destitute of the notch in the 

 bill. This, however, we have found to be a mistake. 



Upper mandible destitute of a notch. 



217. Cephus. Tyste. Bill lengthened, upper mandi- 

 ble slightly bent at the point. C. grylle. 



213. Mergulus. Bill short, margins inflected at the 

 base. Lower mandible contracted at the top. Nasal 

 groove wide. Aha alle. 



B. Wings long and well adapted for flight. 



Apertures of the nostrils prominent. Bill hooked at the 

 point. 



External margins of the bill with lamellate teeth, like the 

 ducks. 



219. Pachyptila. Nostrils tubular^ separate base of 

 the bill enlarged. Procellaria coerulea. 



See Plate H. fig. L A male, c the bill open to exhibit the notch. 



