Fy E'D be 
Vertebrate animals characterized by having the blood cold with oval 
nucleated corpuscles; heart usually with three chambers; circulation 
incomplete; venous and arterial blood intermingled ; aortic arches two, 
which coalesce or anastomose in front of the dorsal vertebree ; reproduc- 
tion oviparous or ovoviviparous; embryo with amnion and allantois ; 
respiration pulmonary in young and adult; lungs with few cells; met- 
amorphoses none; occipital condyles one; rami of the lower jaw in 
several pieces; os quadratum present; nervous system cerebro-spinal ; 
brain small; lateral lobes of cerebellum, corpus callosum, and pons 
varolii wanting ; corpora bigemina upon the upper surface of the brain ; 
epidermal covering in the form of scales or plates. HExcrementitious and 
reproductive organs opening into a cloaca. 
Exclusive of the extinct orders, the following synopsis will refer an 
animal to its proper place: 
KrY TO THE ORDERS OF REPTILES. 
Epidermal! covering in the form of plates, not united with the skeleton; anal slit 
longitudinal; teeth conical, in sockets. . . . . . ~~ CROCODILIA. 
Epidermal covering united with the skeleton forming a carapax and plastron; teeth 
none. : : : A : : ; ; TESTUDINATA, 
Epidermal covering in the form of scales, rarely plates, distinct from the skeleton ; 
anal slit transverse; teeth conical. a. 
a. Eyelids usually present; mouth not dilatable; body usually lacertiloid 
with four well developed feet. . . . . . . LACERTILIA. 
a, Eyelids none; mouth very dilatable; body always serpentiform, without 
feet; abdomen usually covered with large, entire, transverse scutella. 
OPHIDIA. 
CROCODILIA. (Extyralimital.) 
Body lacertiloid, of large size; dermal armor composed of scutes and overlapping 
scales; anal slit longitudinal ; limbs four, well developed, anterior pair shorter, posterior 
feet more or less palmate; fingers five, toes four; nails on the three preaxial digits 
usually present; eyelids three, distinct; auditory openings with valves; external nares 
capable of closure; teeth in a single row, in sockets; tongue thick, fleshy, adherent its 
entire length, and not protrusible ; heart quadrilocular, but with the pulmonary artery 
and aorta connecting ; quadrate bone large; palatines excluding the vomer from the 
