OBSERVATIONS ON A SPECIMKN OF " SULA BASSANA." 335 



flight, taking the prey by a pounce or swoop, and being less decidedly 

 aquatic in habits than the rest of the order — at least with some ex- 

 ception in the family representing the second tendency. We can 

 hardly fail to be led in pursuit of such characters to the Pelecanidaet 

 which are remarkable for the length and power of their wings, swim 

 less than any of the other birds organised for aquatic life, and seize 

 their prey either like the Atagen, or Frigate bird (the most peculiarly 

 Eaptorial of the family), by a swoop from the surface of the water, 

 or, like the Gannett and Pelican, by a sudden stroke from above. If 

 we inquire what family of swimming birds deviates least in figure and 

 flight from the most typical birds, forming a link of connection be- 

 tween the Insessorial and Natatorial orders, and impressing us with 

 the activity and gracefulness of its movements and its union of aerial 

 with aquatic modes of life, we immediately think oi Laridae—ihe Gulls, 

 Terns, and Petrels as certainly occupying the second place. It needs 

 no array of evidence to prove that Anatidae, including swans, geese, 

 and ducks in all their variety, represent the nutritive tendency, and 

 are analogous with the poultry among the orders of birds. They con- 

 stitute the largest and most characteristic of the Natatorial groups 

 — Mr. Swainson's typical family. The lengthened bill and neck, 

 generally elongated figure, and frequently anomalous feet of the Divers 

 {Colymbidae), point out their position as representing the fourth ten- 

 dency in analogy with wading birds ; and finally, the entire unfitness 

 for living out of water or moving much in any other element, with 

 the manifestly low structure as compared with the rest of the order, 

 and with almost all other birds, proves that we are right in assigning 

 the fifth place to Alcidae, the Auks and Penguins. 



It remains to be considered whether, even in the comparatively 

 small and deviative family of the Pelicanidae, an examination of the 

 generic forms will not enable us to mark out sub-families however 

 limited in number of species, again indicating the same tendencies. 

 And here I would name the Frigate birds {Atageninae) as displaying 

 the raptorial tendency ; the Phaetoninae or Tropic birds, whose grace- 

 ful figure, little removed from that o^ Insessorial birds, has caused them 

 to be placed among the Gulls, notwithstanding the beak and the feet 

 •bowing its connection with the Pelicans, will naturally take the se- 

 cond place. 



The bird which has given occasion to these observations, with the 

 larger nearly-related genus Graculus, the Cormorant {Phalacrocorase 



