INTRODUCTION. xix 



lum confluent with its keel. Carotids double. Palate highly desmogna- 

 thous. Reproduction altricial; young psilopasdic or ptiloptedic. Eggs 

 three or fewer. 



Li. LONGrlPENNES. (To most of the characters of the group here given 

 the o-enus Halodroma is a signal exception, though unquestionably belong- 

 ino- here.) Feet palmate. Tibiaj feathered. Legs at or near centre of equi- 

 - librium, affording horizontal position of axis of body in walking. Knee 

 scarcely buried in common integument; tibia sometimes with a long apo- 

 physis. Hallux elevated, free, functionless ; very small, rudimentary, or 

 wanting. Rostrum of variable shape, usually compressed and straight to 

 the hooked end, sometimes entirely straight and acute, commonly length- 

 ened always corneous, without serration or true lamellag. Nostrils of vari- 

 ous forms, tubular or simply fissured, never abortive. No gular pouch. 

 Wings very long and pointed, surpassing the base and often the end of the 

 large"^ well-formed, few-feathered tail. Carotids double. Palate schizog- 

 nathous. Reproduction altricial ; young ptiloptedic. Eggs three or fewer. 

 Habit highly volucral. 



M. PYGOPODES. Feet palmate or lobate. Tibiae feathered, often with 

 a long apophysis, always buried in common integument nearly to the heel- 

 joint, necessitating a more or less erect posture of the body on land, where 

 progression is difficult. Hallux small, elevated or wanting ; feet lobate or 

 palmate. Bill of indeterminate shape, wholly corneous, never lamellate or 

 serrate, nor with gular pouch. Nostrils not abortive. Wings very short, 

 reaching scarcely or not to the base, never to the tip, of the short, some- 

 times rudimentary, taih Palate schizognathous. Carotid usually double, 

 sometimes single (in Podiceps and Mergulus). Nature altricial or praecocial ; 

 young ptilopajdic. Highly natatorial. 



IV. SPHENISCI. With general characters of the last group, but dis- 

 tinguished by unique ptilosis and wing-structure, etc. Plumage without 

 apteria, of singularly modified scale-like feathers on most parts ; no devel- 

 oped remiges. Wings unfit for flight, insusceptible of perfect flexion or 

 extension, very short, with peculiarly flattened bones and stable articulations. 

 Skeleton non-pneumatic. Many bones, terete in ordinary birds, here flattened. 

 Metatarsal bone flattened transversely, doubly fenestrate. Hallux elevated, 

 lateral, minute, free. No free poUex. Two anconal sesamoids ; patella 

 from double centres ; tibia without apophysis ; a free tarsal ossicle. Ster- 

 num with long lateral apophyses. Pelvic connections unstable. Caro- 

 tids double. Comprising only the Penguins. Confined to the Southern 

 Hemisphere. 



Having thus presented and defined an arrangement of the higher groups 

 into which recent Carinate birds are susceptible of division, I next proceed 

 to the consideration of the North American Families of birds which the 

 autliors of the present work have provisionally adopted as suitable to 

 the end they had in view. Professor Baird urges the caution that the 

 scheme is intended merely for the convenient determination of the North 

 American species, aware that in many instances diagnoses or antitheses of 

 entire pertinence in such application would fail or be negatived by con- 

 sideration of the exotic forms. The arrangement of the families here 

 adopted is essentially that presented in 1858 in Professor Baird's " Birds of 



