STEGANOPODES. 73 



Order STEGANOPODES.— The Totipal- 

 MATE Swimmers. (Pagei.) 



Families. 



a}. Nostrils distinct ; lateral toes neai"ly equal, and nearly as long as the middle 

 one; whole head feathered. 



Bill conical, compressed, pointed, without terminal hook, or unguis ; 

 culmen curved ; edge of upper mandible very concave ; tail short, gradu- 

 ated, the middle pair of feathers, in adults, very narrow and greatly 



elongated Phaethonlidse. (Page 73.) 



a^ Nostrils not perceptible ; lateral toes unequal, and one or the other of them 

 much shorter than the middle one; head partly naked. 

 b^. Bill conical, the tip of the upper mandible without distinct hook, or 

 unguis. 

 c^ Bill very thick through the base, the tip slightly curved; tail about 

 half as long as the wing, gi*aduated or cuueate, the feathers narrow- 

 ing toward the rather pointed tips Sulidae. (Page 74.) 



d. Bill slender, the outlines (culmen especially) nearly straight; head 

 very small, the neck extremely long and slender; tail nearly as long 

 as the wing, rounded (fan-shaped when spread), the feathers very 

 broad, the middle pair transversely corrugated in the adult. 



Anhingidse. (Page 76.) 

 b"^. Upper mandible terminated by a distinct hook, or unguis. 



c\ Tarsus moderately lengthened, much longer than the hind toe, including 

 its claw. 

 d\ Bill shorter than middle toe, compressed ; gular sac small, scarcely 

 distensible ; outer toe much longer than middle. 



Phalacrocoracidae. (Page 77.) 

 (P. Bill much longer than middle toe, much flattened ; gular pouch very 

 large, and greatly distensible ; outer toe shorter than middle. 



Pelecanidae. (Page 81.) 

 c^. Tarsus excessively short, hardly equalling the hind toe (including its 

 claw) in length. 



Wings and tail excessively lengthened, the latter deeply forked ; 

 middle toe much longer than the outer, its claw flattened and 

 fringed on inner edge ; webs very small, occupying less than 

 half the space between the toes Fregatidse. (Page 82.) 



Family PHAETHONTIDiE.— The Tropic Birds. (Page 73.) 



Genera. 



(Characters same as those of the Family) Phaethon. (Page 74.) 



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