SPECIES OF RAT IN ENGLAND. 109 



divided into elongated pellets, after passing away from the valvular 

 part of the canal. 



The aims is placed close under the tail, quite behind, and apart 

 from, the genital aperture. 



"The kidneys are very convex, unlobulated, and of considerable 

 size. The supra-renal bodies, yellowish white, large. 



Uterus bilobed,with a coiled Fallopian tube, ovoid shaped ovary. 

 The right horn held three, the left five foetuses advanced in de- 

 velopment. Organs of chest, and head not examined. 



The brown rat is altogether a larger and stronger animal, 

 measuring in length of head and body 9 or 10 inches, or even more, 

 with a tail not so long in proportion as the black rat, being scarcely 

 so long as the head and body together. Head larger and stronger 

 in proportion. 



Colour of body yellowish brown, gradually passing into white 

 on all the under parts of the body, of the two kinds of hair the 

 undergrowth predominates, and thus the fur feels thicker, but 

 softer, than on the black rat. Muzzle blunter and broader. Eyes 

 much the same as in the black species. Whiskers black and 

 white, though chiefly black; on the whole, not so long as in the 

 other species. Ears about f inch long, therefore shorter, they are 

 more broadly ovate, and nearly covered on both surfaces with 

 short hair, colour of skin of ears much lighter than in black rat. 

 Tail round, has at least 200 rings of epidermic scales, with whorls 

 of hair as in the M. JRattus, only the hairs are dark brown, and 

 the rings of scales and skin of tail white, instead of black. Mammce, 

 alike in the two species. Feet, pale flesh-coloured beneath, 

 covered with white hair above. Digits and pads of soles alike 

 in both species j length of sole of fore foot f inch, of hinder 1 j inch. 

 Teeth same in number and disposition, but larger, more robust, 

 and the lower jaw also somewhat larger in proportion to the skull, 

 and of rather difl'erent form from that in the black rat. 



All the viscera larger ; stomach shaped a good deal like that of 

 black rat, but its left end produced into a distinct bulbous- 

 like pouch, between which and the rest of the organ is a marked 

 constriction. 



The cuticular lining of left end seems to vary in extent in 



