KODENTIA. J 13 



The Black Hn-t (M.rathts, Lin.), which the ancients have not ulUulcd to, and \vhich appears to have cmerc-d 

 Europe during the middle ages. It is more than double the size of the Mouse in all its dimensions. 'I'ha fur is 

 blackish [with the ears much larger, and the tail longer, than in the following. Tliere is a brown variety of this 

 species, which is common in Paris, and ai^iears to have been figured by M. F. Cuvier as the Surmulot.] 



The Brown Rat, or Surmulot (J/, decuinanus, Lin.), which did not pass into Europe till the eighteenth century, 

 and is now more common in large cities [and elsewliere, except in remote isolated localities,] than the Black Hat 

 itself; it is a fourth larger than that species, and is also distinguished by its brown colour. This animal appears to 

 belong to Persia, where it lives in barrows : it was not till 1727, that, after an earthquake, it arrived at Astracan, 

 by swimming across the Volga. 



It would seem that the Black Rat, also, originated in the East ; and these two large species, together with tlie 

 Mouse, have been transported in ships to all parts of the globe. 



[Of the very numerous others, it must sulhce to name the huge Bandicoot Rat of India {M. giqanteusy 

 Ilardw.), which is much larger than the Surnmlot. Those indigenous to South America have more complicated 

 folds of enamel to their molars.*] Some have spines mingled with their fur, as 



The Cairo Mouse (J/, cahirinaa, Geoff.), which has spines on the back in place of hairs, and was noticed by 

 Aristotle. 



[Only two strielly indigenous British riiice have hitherto been described : the tirst, extremely diminutive, is the 

 Harvest ^Jouse {M. jncs-'iorin.s, Shaw), with short ears, and red fur similar to that of the Common Dormouse : it 

 constructs a beautifid round or pear-shaped nest, attached to corn-stems, or p'aced in low bushes ; and is remark- 

 able for its tail being slightly prehensile at the extremity. The second is commonly termed the Long-tailed Ficid 

 Mouse (M. st/h-a/icKx), and might almost form a separate subgenus ; it rather exceeds the common Mouse 

 in size, with proportionately larger ears, and much larger and very brilliant eyes; a brown mark in the centre 

 of the chest: it is a pretty and very active species, more generally diffused than the Harvest I\Iouse, and never 

 enters buildings, where the other is often carried with the sheaves.] 



Warm climates produce Rats, similar in every detail to those of which we have just spoken, except 

 that thcii- tails are more hairy. Sucli are 



I-hjpudccus varkgatiis, Licht., var. flava; Meriones si/cnensls, Id. To which mast be added the Arvicola 

 mesnor, Le Coute ; Arc. horiemiSy Harl., or >Si/gvwdon, Say, distinguished however by its hairy ears, hke 

 ibe Ofomi/s. 



Anotlier group, also with a hairy tail, but the teeth of which wear away faster, comprises the Ili/pud-ctis obesv^j 

 Licht., the Mas rufiraudiis, Id., and also the Meriones nericeus of the same natarali::>t, characterized by the 

 projecting ridges of the molars, which alternately catch in each other. 



We have then to group the Neoioma _fforidanum of Say, or the Arvicola floridana of Harlan, and the Arvicnta 

 qossypina, Le Conte, two species which, size excepted, are very similar even in their colours, and the molars of 

 which, provided with roots [after a while], when worn a little, have crowns similar to those of the Arvicola:. [The 

 tail in one of them is covered with hair of tolerable length. Both inhabit North America. 



RcHhrodon, Waterh., requires also to be introduced here, distinguished by its grooved upper incisors, its arched 

 and Rabbit-like head, great eyes, and large and round ears. Three or four species are known, from Sffiitli 

 America, where they "ivere discovered by Mr. Darwin. 



The Pscudomys of Gray is another Rat-like animal, remarkable for inhabiting New Holland : the anterior molar 

 of its lower jaw is however more compressed and elongated, and there is a claw on its rudimentary thumb. The 

 species, Ps. ausiralis, inhabits holes in swampy places, at Liverpool plains. 



It is necessary also to introduce here the Ilajyalofis alhipes, Licht.; Cottiluri/s consfricfus, Ogilby ; another 

 rodent from New Ilolland, the size of a Rat, with delicate ample ears, and along, hairy, and somewhat tufted tail. 

 It is remarkable for constructing an above-ground habitation, so firmly interlaced with thorny twigs externally, 

 as to repel the Dingo or semi-wild Dog of that country.] 



The Gerbils {Gerhillnf^y Desm. ; Meriones, Ilhg.) — 

 Have molars scarcely differing from those of the Rats, merely becoming sooner worn, so as to form 

 transverse ridges. Their upper incisors are furrowed \\ith a groove ; their hind feet are somewhat 

 longer in proportion than those of Rats in general, with the thumb and little toe but slightly sepa- 

 rated: their tail is [very] long and hairy, [and generally tufted]. 



The sandy and warm parts of the eastern continent produce several species, [mostly of a light huff colour, white 

 underneath]. 



The Merions {Meriones, F. Gav.), — 



Wliich we separate from the Gerbils, have the hind feet still longer, the tail nearly naked, and a ver) 

 small tooth before the superior molars ; characters which approximate them to the Jerboas : their 

 superior incisors are grooved, as in the Gerbils, and their toes also are similar. 

 There is a small species in North America, Mus canadensis, Pen.; Dipus canadensis, Shaw; D. amer/canns, 



* C-r-aifj uf these, lUc upper lip of M'Uich U .scirccly fissured, com I South Africa, which constitute the Dnidronn/^ n{ Snillh : ti.cy Mjrvrtelr 

 poae the Hvlochilu3,'Rtmidt. There are also some iirbureal I\Iice iii I .hirer in atructurc from the British Htirvest Muuse.-HD. 



