Hurler — Eerpetology of Missouri. 127 



found any at that place. At Poplar Bluff, Butler County, 

 it is quite plentiful. 



Dates of capture. — Apr. 26; May 15, 28; Sept. 5. 



Class Keptiliu. 



Exoskeleton in the form of horny scales or bony plates. One occipi- 

 tal condyle. Mandible present, each ramus of several bones. Verte- 

 brae without terminal epiphyses. Generally no diaphragm (an incom- 

 plete diaphragm is present in crocodiles). Respiration always by 

 means of lungs, sometimes aided by the walls of the pharynx. Heart 

 generally with three, sometimes with four, chambers. Two aortic 

 arches. Blood not warm; red corpuscles nucleated. Alimentary canal 

 terminating in a cloaca. Oviparous or ovoviviparous. (Garman.) 



The existing reptiles are divided by Dr. H. F. Osborne 

 into two sub-classes, Diapsida and Synapsida. To the 

 latter belongs only one existing order, viz., the turtles 

 {Testudinata), which are characterized by having the 

 scapular arch internal to the ribs, while in the three ex- 

 isting orders of the Diapsida it is external. These orders 

 are: Crocodilini (also called Loricata or Emydosauria), 

 characterized by two-headed ribs ; RhyncUocephalia , rep- 

 resented by a single surviving genus in New Zealand 

 {Sphenodon), superficially resembling a lizard, but distin- 

 guished from the next order by having, among other char- 

 acters, the quadrate bone immovably fixed to the adjacent 

 cranial elements by suture, while in the Squamata, em- 

 bracing snakes and lizards, it is loosely articulated with 

 the cranium at the proximal end ; the last two orders have 

 one-headed ribs. (Stejneger.) 



Subclass Diapsida. 

 Primarily with double or separated temporal arches. 



Order SQUAMATA. 



The order Squamata consists of three sub-orders — the 

 chameleons {Bliiptoglossi), the lizards (Sauria), and the 

 snakes (Serpentes). Of these only the two latter orders 

 are represented in Missouri. 



