REPTILES AND AMPHIBIANS 
lizard the body is dry and hard, the epidermis being 
converted into regularly arranged scales, while there 
are no glands in the skin except at the beginning of the 
thighs, where a row of pores void on to the exterior 
the secretion of the femoral glands. The limbs of the 
amphibian are short and only four-toed, rot much 
used in locomotion. Those of the lizard are five-toed 
and longer, and very much used in locomotion. On 
the neck of the menobranch will be noticed three 
pairs of fringed red outgrowths of the body, which 
are the gills; by means of these the animal at least 
partially breathes. It has also lungs. Close to the 
gills are, on each side of the neck, two perforations 
which lead into the pharynx; these are the so-called 
_ gill clefts. In the lizards we find not the slightest trace 
of these last two structures. The animal has only 
lungs, with which alone it breathes. If we dive into 
the anatomy of the two animals we shall emerge with 
other characters, which completely distinguish them. 
The skull of the Menobranchus is fixed on to the vertebral 
column by two joints or condyles while there is but 
one median condyle in the lizard. The heart is three- 
chambered in both; but in the amphibian the origin of 
the aorta from the ventricle is dilated into a thicker 
walled tube, in which are several series of valves regulat- 
ing the flow of the blood when it leaves the heart to 
pass through the arterial system. In the lizard there 
is no such dilated “conus arteriosus,’ and the persist- 
ence of this conus in the amphibian is a mark of its rela- 
tionship to the lower lying fish, where such a conus always 
exists. The menobranch has no sternum or breast-bone 
formed by the union of the ribs ventrally ; there 7s such 
a sternum inthe Lacerta. The Menobranchus lays eggs 
as does the Lacerta ; but the eggs of the former are smaller 
than those of the latter, and do not contain nearly so 
much yolk. Moreover there is no hard shell such as 
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