354 NATATORES. 



whitish eggs, and to subsist on insects and their larvae, and 

 on the spawn of fishes and reptiles. 



The last-mentioned species has been seen (in winter) in the 

 island of Lewis, the extensive and dreary flats and moors of 

 which are worth searching, not only for the rarer species in 

 winter, but for the nests of some of the northern birds in 

 summer. 



GOOSANDERS (Mergus). 



Birds of this genus have the bill more slender and cylin- 

 drical than that of the ducks, serrated with sharp reflected 

 teeth along both mandibles, and with the nail at the tip 

 hooked ; so that the bill is altogether less of a dabbling, and 

 more of a prehensile instrument. The internal structure 

 also indicates that they feed more exclusively upon animal 

 matter ; and the position of their feet, the form of their 

 wings, and the great enlargement of the lower part of the 

 trachea, all adapt them well for diving in quest of fishes, 

 which form the chief part of their food. The difference in 

 plumage between the males and females, and the males in 

 the young and the adult state, has, as in the case of many 

 other birds, led to some confusion in the descriptions. 

 Four species are enumerated as British one resident, the 

 others visitants or doubtful. They all belong to the northern 

 ornithology. 



RED-BREASTED MERGANSER (MergiiS SCrratus). 



These birds are very awkward walkers, in consequence of 

 the shortness and backward position of their legs ; but they 

 swim and dive well, and are of powerful flight, ranging over 

 a great extent in latitude in the course of the year. The 



