122 MAMilALU. 



of the first grand division are distinguished by having the inferior projecting angle of the 

 lower jaw svibquadrate, and not ta|)criug to an acute pomt. In this group, or series, range 

 first the Sciiirid/r, or S(|uirrels and ilarmots, followed by the Dormice, and next by the 

 Jerboas, wluoh latter requn-e to be interpolated between the SchiridcE, and the Miiricia or 

 Rats ; the Jerboas evincing several jieculiar points of relationslii[i with the Dormice : the 

 Arvicolida;, or Muskquash, Voles, and Lemmings, together with the Guaffi'es [Geomys), 

 follow the Muridce, and then succeed two isolated genera, — Castor and Helamys, which seem 

 to constitute particular families : all these successive groups being readdy distinguishalde by 

 the structure of the cranium and inferior jaw, combined with other characters. The meniljcrs 

 of the next great group have the inferior angle of the lower jaw acute, and usually four equal 

 molars on each side above and Ijelow, having their folds of enamel gradually more complex. 

 Abrocoma, Odoilnii. Poi'phago'nujs, Cfeiio/iii/x, Capromtjs, Echi/mys, Myopotamus, Auhicodon, 

 then Hystrix and its allies, and near to the last Cielogenys and Dosyprocta, form a very intel- 

 ligible series, after which the bony palate contracts anteriorly, and we arrne at the Cavidce, 

 or Capybara, Moeo, and Cavies, succeeded by the Chincldllida;, and lastly by the Hares and 

 Pikas, near wliich it may be that the Ctcnodactyle holds its station. In the terminal genera, 

 or the LcporiilfP, the angle of the jaw suddenly ascends. It is ]u-obable that multitudes of 

 existini^ rodents still remain to be discovered, a knowledge of some of which may assist in 

 iujproving the general arrangement. But few have hitherto been met with in tlie ancient 

 tertiary deposits, and those of genera still extant, as that of the Donnice in particular.] 



THE SIXTH ORDER OF MAMMALIANS,— 



EMENT.VTA,— 



Or quadrupeds without teeth in the forc-]iart of their jaws, constitute our last principal divi- 

 sion of unL'uiculatcd animals. Although brought together liy a purely negative character, 

 they have, irevertheless, some positive mutual relations, particularly in the great claws which 

 encompass the ends of their toes, and i\liicli nune or less approximate to the nature of liiiols; 

 also Ijy a certain sloiMiess, or want of agility, obviously arising from the peculiar organization 

 of their limits. There are certain tolerably well-marked intervals, however, in these relations, 

 which subdivide the order into three tribes. . 



TlllO T,VRDIGR.\D.\. 



Compose the first of these divisimis. They have a short face. The name refers to their 

 excessive slowness, consequent upon a construction truly heteroclite, in wliieh nature seems 

 to have amused herself liy producing somethiug imperfect and grotesque. [A most strange 

 assertion on the ]iart of Curier, originating from a want of kno^^ledge of the peculiar habits 

 of these singular animals.] The only existing genus is that of 



The Sloths [as lliey are badly named] {Bradypus, Lin.), — ■ 

 Which have cylindrical molars, and sliarp canines longer than tlicse molars ; two pectoral manima^ ; 

 and the toes completely joined by the skin, and only marked externally liy enormous compressed and 

 crooked claws, which, when at rest, are always bent towards the palms, or soles, of the fore and bind 

 ffct. Tlie latter are obliquely articulated on the leg, and apply only their outer edge; the ];lialange3 

 of the toes are articulated by serrated ginglymi, and the first, at a certain age, becomes sulilcrcd to 

 tlie metacarpal or metatarsal hones, wlurli ab", for w.ant of use, become similarly ancbylosed. To this 

 inconvenience [?] in the organi/,atj(iii of the extremities is added another, not less great, in tlieir 

 j,noportions. Their anus and fore-arms are very much longer than tlicir thighs and legs, insomuch 



