ALCAD.E. , 25 



with the exception of the last in the series (the great 

 Auk), whose quills are too short to allow of such 

 locomotion : they are all, however, admirable swim- 

 mers and divers, and many of them while swimming 

 are immersed up to the neck in the water. They 

 nidificate in the clefts and fissures of rocks, some 

 species laying but one, and others two eggs : they all 

 feed on small fishes, Crustacea, vermes or mollusca, 

 or marine vegetables. 



