REPORT 



MAMMALS OF OHIO. 



BY A. M. BRAYTON. 



The Mammals are air-breathing, warm-blooded vertebrates, having the 

 skin more or less covered with hair; respiration never by branchise, but 

 after birth by lungs ; heart and lungs in the thorax, separated from the 

 abdominal viscera by a muscular diaphragm ; the blood with red non- 

 nucleated blood-corpuscles; blood undergoing a complete circulation, 

 being received and transmitted by the right half of the quadrilocular 

 heart to the lungs for aeration, and afterward returned by its other half 

 through the system ; aorta single and reflected over the left bronchus. 

 The cerebral hemispheres are connected by an anterior commissure, 

 and a transverse superior commissure, the corpus callosum, the latter more 

 or less roofing in the lateral ventricles ; skull with two occipital con- 

 dyles, one each side of the foramen magnum ; lower jaw composed of a 

 pair of simple rami, and articulated directly by convex condyles with 

 the squamosal bones. Viviparous ; foetus developed from a minute egg, 

 and provided with an amnion and allantois ; young nourished for a time 

 after birth by milk secreted in the mammary glands of the*mother. 



