MAMMALIA. 



(2. PLECOTUS.) Ears very large, much longer than the head, with 

 their inner edges united at the base above the eyes : grinders 

 five above and six below on each side. 



(3. BARBASTELLUS.) Ears moderate, united at the base above the 

 eyes: a flat naked space on the forehead surrounded by a 

 membraneous edge : grinders four on each side above and below. 



//. Incisor, canine, and molar teeth not all present, 

 or not forming a continuous series. 



ORDER III. GLIRES. 



Incisors two in each jaw, large, and strong, remote 

 from the grinders: tusks none: toes distinct, with 

 small conical claws. 



* Furnished with strong clavicles. 



14. SCIURUS Grinders simple, with tubercular 



summits, five above and four below on each side : upper 

 incisors chisel-shaped ; lower ones pointed, compressed 

 laterally : toes long, armed with sharp claws : tail long 

 and bushy. 



15. MYOXUS. Grinders simple, their summits mark- 

 ed with transverse ridges of enamel, four on each side 

 above and below : hair very soft and fine : tail very long, 

 somewhat bushy. 



16. MUS.-^-Grinders simple, with tubercular summits, 

 three on each side above and below : upper incisors wedge- 

 shaped, lower ones compressed and pointed: tail nearly 

 naked, annulated with scales. 



17. AR VI COL A. Grinders compound, with flat sum- 

 mits, the enamel appearing in ridges on the surface : upper 



