52 MANUAL OF NATUEAL HISTORY. 



vated, sometimes very small; claws curved, 

 sometimes very acute ; wings long and point- 

 ed. The Skimmers ( lihynchopince) have 

 lower mandible much longer than upper, and 

 both suddenly compressed from base, and 

 truncate. 



6. FAMILY. Pelicans (Pelecanidae). Bill long, 

 strong, pointed or hooked, lateral margins 

 sometimes serrated ; nostrils basal ; tarsi 

 short ; all the four toes connected by a mem- 

 brane; throat sometimes furnished with a 

 dilatable pouch ; wings long and pointed. 



KEPTILES. 



The Reptiles, though not a very extensive group, 

 present numerous points of great interest to the 

 observant naturalist. Among them is to be found 

 extreme diversity of external configuration, more 

 so, perhaps, than in any other class of vertebrate ani- 

 mals. They include, among their varied forms, the 

 gliding, hissing Serpent ; the lively, active Lizard; the 

 gigantic Crocodile ; and the huge, unwieldy Turtle. 

 Yet all these, though differing so much from each 

 other in outward appearance, nevertheless possess 

 a sufficient number of characters in common as to 

 enable them to be united into one class. They are 

 all cold-blooded creatures, and their movements are 

 more sluggish than in either of the preceding classes; 



