AVES. 75 



slightly inclining at the tip ; lower mandible with the gonys 

 ascending : feet short ; anterior toes fissopalmated ; hind 

 toe lobated : claws broad, and much depressed : wings with 

 the three first quills nearly equal, and longest : tail wanting. 



101. COLYMBUS Bill rather longer than the head, 



straight, robust, nearly cylindrical, sharp-pointed ; the 

 tomia of both mandibles inflected ; gonys ascending : feet 

 short ; anterior toes long, entirely palmated ; hind toe short, 

 and lobated : claws depressed : wings with the first or 

 second quill longest : tail very short, rounded. 



III. ALCID^E. Bill very much compressed, often 

 transversely grooved at the sides : wings short, 

 sometimes wholly unfit for flight : legs placed 

 at the extremity of the body : feet three-toed, 

 entirely palmated. 



102. URIA. Bill moderate, strong, straight, convex 

 above, much compressed at the sides, sharp-pointed ; upper 

 mandible slightly deflected at the tip ; gonys of the lower 

 mandible ascending ; tomia curving inwards from the base 

 to the middle : nostrils basal, lateral, pervious, elliptic- 

 linear, half concealed by a plumose membrane : tarsi very 

 much compressed : wings very short ; first quill longest : 

 tail short, of twelve feathers. 



103. MERGULUS Bill shorter than the head, 



rather thick, convex, conical, slightly curved, covered at 

 the base with downy feathers ; both mandibles notched at 

 the tip : nostrils basal, lateral, round, partly concealed by 

 a plumose membrane : wings not reaching to the tail ; first 

 and second quills equal, and longest : tail short, of twelve 

 feathers. 



104. FRATERCULA Bill shorter than the head, 



thick at the base, very much compressed anteriorly, higher 

 than long, the culmen more elevated than the crown of the 

 head ; both mandibles arched, transversely furrowed, and 

 notched at the tip : nostrils basal, marginal, oblong-linear, 



