XXX SYSTEMATIC ARRANGEMENT OF GENERA. 



surface feeders, living on fisli and other animal substances, either 

 captured alive, found floating, or thrown ashore. 



129. Sterna (Tern). Bill as long as the head or longer, slightly 

 compressed, slender, and ta])ering to a sharp point ; mandibles of 

 equal length, the u])per slightly bent downwards towards the tij) ; 

 three front toes connected l)y a membrane, tlie edge of which is 

 deeply curved inwards ; hind toe free ; wings pointed ; first primary 

 longest ; tail forked. Page 562. 



130. Laiius (Gull). Bill moderate, strong, sharp-edged above, 

 compressed, slightly curved towards the point ; upper mandible 

 longest ; three front toes perfectly jialmated ; hind toe high on the 

 tarsus ; first primary nearly equal to the second, which is longest ; 

 tail even, or but slightly forked. Page 575. 



131. Lestris (Skua). Bill moderate, strong, rounded above, 

 compressed towards the tip, which is decurved ; base of the upper 

 mandible covered with a cere ; nostrils far forward, diagonal, per- 

 vious ; hind toe very small, scarcely elevated ; claws large, strong, 

 much curved ; the middle tail-feathers more or less elongated. 



Page 591. 



132. Procellaria (Fulmar), Bill shorter than the head, strong, 

 and hooked at the end ; the upper mandible divided by indented 

 lines into four parts, lower w^itli a longitudinal furrow on each side ; 

 tube of the nostrils extending along half the length of the ridge of 

 the upper mandible, and opening by a single orifice ; hind toe a 

 simple claw. Page 597. 



133. PuFFiNUS (Shearwater). Bill as long as the head or longer, 

 slender, hooked ; both mandibles curved downwards ; nostrils in a 

 double tube extending one fourth of the length of the bill, and 

 oi)ening by a double orifice ; hind toe a simple claw ; tail rounded. 



Page 599. 



134. Thalassidroma (Petrel). Bill shorter than the head ; 

 much compressed in front, in other respects as in Puffikus ; nasal 

 tube single, extending half the length of the bill, but o])ening by 

 a double orifice ; tarsi slender, rather long ; hind toe a simple claw ; 

 wings acuminated ; tail even at the end, or forked. Page 602. 



