360 ALCA IMPENNIS. 



that part being high and compressed ; the dorsal line at first 

 convex, then ascending and concave to the end ; the sides 

 flat, with twelve transverse grooves, fainter than those of the 

 upper mandible ; the edges sharp, the tip deflected. 



Nostrils basal, linear. Eyes rather small. Apertures of 

 ears very small. Feet placed far back, short ; tarsus short, 

 compressed, anteriorly scutellate, scaly on the sides. Hind 

 toe wanting ; outer toe nearly as long as the third or middle, 

 inner toe much shorter ; all with numerous scutella and 

 several rows of angular scales, and connected by narrow 

 reticulated membranes ; the inner and outer toes connected 

 at the base, the middle toe only for a quarter of an inch. 

 Claws rather small, narrow, arched, convex above, obtuse. 



Plumage dense, blended, very short, on the head and 

 neck short and velvety. Wings extremely small, but of the 

 same form and structure as in the Razorbill and Guillemots ; 

 the primaries narrow and tapering to an acute point, the 

 first longest, the rest rapidly graduated, their coverts long ; 

 secondaries short and broad, scarcely longer than their 

 coverts. Tail short, pointed, of fourteen feathers. 



Bill black, with the grooves white. Feet and claws 

 black. The head, throat, sides, and hind part of the neck, 

 and all the upper parts, black ; the throat and sides of the 

 neck tinged with chocolate-brown ; the wings with greyish- 

 brown ; the head, hind-neck, and back glossed with olive- 

 green. A large oblong patch before each eye, the tips of 

 the secondary quills, and all the lower parts, white. 



Length to end of tail 25 inches ; wing from flexure 7 ; 

 tail S ; bill along the ridge S-^, along the edge of lower 

 mandible 4^, its depth at the angle 1-^ ; tarsus 2 ; middle 

 toe 2-j%, its claAV -j^ ; outer toe 2^-7y, its claw -j^ ; inner toe 

 S-Jtt, its claw -j^. 



Adi'lt in Winter. — It appears to undergo, in autumn, 

 the same change as the Guillemots and Razorbill, as Dr. 

 Fleming states : — " In winter, the brownish-black of the 

 throat and fore-neck is replaced by white, as I had an oppor- 

 tunity of observing in a living bird, brought from St. Kilda, 

 in 1822." 



