HYSTRICIDA. 



HYSTRICIDJi. 



1-1 



to the lo 



Aooordun to Mr. IMrwin UM animal is known by the name of 

 Amm, sad it i* exewdiacl* common in the neighbourhood of several 

 tow** oo UM banks of the Bio Plata, aometimee frequenting the sand 

 hHVT>t*. or the bJgr-row* formed of the Aynn and Op**ti* ; but 

 snarahy phtor* covered with aquatic plant* appear to be preferred. 

 Where UM soil i* dry it make* a burrow, but otherwise it lies con- 

 esejij amidst the herbage. It generally comes out to feed in the 

 iioft, and if UM day b* ftl-uiy it will likewise make it* appear- 

 in the moraine. In Bolivia, Mr. Bridge* state* this animal is 

 i low lands, and in this respect differ* from the Caria 

 always found at a considerable elevati n. It in 

 DO uncommon ia field* in the neighbourhood of Chuquisaca and 

 Cnehahemba ; and Uke* *helter amougut the loose stones of the walk 

 by which UM Arlde are inclosed. 



Dr. Reafger eays that the A pern is found throughout Paraguay, 

 and ritrn-t* southward a* far a* 35* 8. lat, he has himself not only 

 met with the animal (with which he is well acquainted) in those parts, 

 but liktwiM in Hnuil. both iu Bahia and in Pernambuoo. 



In Paraguay it generally frequents moist situations and near the 

 borders of forests, but it never occur* either in the forests or in the 

 open field*. It lives in little societies (according to the same author) 

 of from six to fifteen individuals, in the impenetrable groves of 

 BrotiielUn ; and it* presence is detected by numerous little beaten 

 path* which it forma amongst these plant*. It feeds early in the 

 morning and after (unset in the evening, but never (trays far from 

 its home. The Apcrea brardt but once in the year, and then has but 

 one or two young. On this and other grounds Dr. Rengger thinks 

 the Aprrt* is not the origin of the Domestic Guinea Pig. 



C. Inropfya, the White-Rumped Cavy. Incisor teeth white ; on the 

 upper parts of the animal of mixed brown black and brownish-yellow 

 colours ; throat, chest, and abdomen white. It inhabits Brazil. 



Vfdrorlttma, llriw.ui; C'apykara, Marcgrave; Capyigoua, D'Azara; 

 Cochoo d'Eau of Dec Marobais ; Irahubo of Qtimilla, Capivard of Kroger, 

 t'spuguaraof DobriUhof, Cabiai of Buffou, Niimpoou of the Botocudo 



' ' . : 



Indians. 



A A | 



Dental formula : Incisors, - ; molars, 



20. 



Molars compound, the posterior teeth the longest, and formed of 

 onmerou* lamina 1 , which are simple and parallel ; the laiuinte of the 

 anterior molars forked. 



T*eU of Oifftun. r. Carter. 



At a meeting of the Zoological Society of London (1832), Professor 

 Owwi, on the occasion f oilnLiiiug a Urge old cranium of the Copy- 

 t*r* Ulnoclng U> M. I >e l> Koun, remarked, that peihaps the most 

 iti-p|inary instance of Uie enlarged view* which result from un- 

 wearied ob rration of the internal structure of animals is afforded 

 bj Cuvin / bold enunciation of the affinity of the Elephant to that 

 order uf the Mammalia which con'xina tlie most minute forms of 

 UM claw ; aoH. in 'M.|- it of that sfflnity, adduced the alveolu 

 laot oralar tooth tn M . be la Kons's specimen as illu.tratm- in od.li- 

 Uooal aoelofy b-tuwn the ni/ilar* of the Rodent and those of the 

 Bkpbant, nau.ely. that Ui* iinmW of transverse laminn increases as 

 the jaw tuUrgts with sge, the whole number not coming into use at 



" In the Capyban," says Professor Owen, " the posterior grinders, 

 like those of the Elephant, present a greater number of component 

 lamina) than the anterior one, which are of earlier formation. Those 

 of the upper jaw, according to the figure and description in the 

 'Ossemens Foasilee' (V. pL 1, p. 24), are composed of eleven lamina;, 

 <>f which sll but the first, which is notched externally, are simple. 

 ID the figure too. it is worthy of observation that the last or eleventh 

 lamina is imperfect, and exhibits a construction analogous to the 

 imperfectly-formed laminae or denticles iu the elephant's griii<l> r, 

 namely, a divi-imi into com|>onrnt column*. In the work 

 Cuvier, ' Sur les DenU des Maoimiferea,' the number of lamina! in 

 the Inst grinder of the upper jaw of the Capybara is stated as ' once 

 ou douze ; ' but eleven only are exhibited in the figure, and we may 

 suppose therefore the doubt as to the precise number to be founded 

 on uncertainty as to the propriety of considering the first deeply- 

 notched lamina as single or double. In the cranium in the College 

 Museum the number of the laminae is twelve, the forked one being 

 regarded as single. In M. De la Foua's specimen the alveola clearly 

 indicate that the number of laminae of the last molar had been thir- 

 teen, with the rudiment of the fourteenth ; the extent of the grinding 

 surface is however proportionally longer than would result from tin- 

 additional laminae alone ; for as these lamina! do not cease to grow so 

 long as the animal lives, they increase iu thickness as age advances." 

 (' Zool. Proc.') 



Mr. Morgan (' Linn. Trans.' vol. xvi.) describes the stomach as formed 

 by a single membranous bag ; and, as in other mamtniferous vegetable 

 feeders in which this simple form of stomach is found, the cuwum 

 as large and complicated in proportion. Finding nothing requiring 

 particular notice in the rest of the alimentary canal, Mr. Morgan pro- 

 ceeded to examine the structure of the mouth and throat. After 

 noticing the considerable extent of the grinding surfaces of the molar 

 teeth, he remarks that it must be obvious how necessary such an 

 arrangement of parts must be to the health of the animal, when tln> 

 nature of its food and the simple structure and limited function- of 

 its most important digestive organ are considered, a provision b'-injj 

 thus made for the proper mastication of the hard vegetable sub- 

 stances upon which the animal must occasionally subsist. But Mr. 

 Morgan found another structure, uudescribed up to the time wi,. n 

 he made his examination, by which the process of perfect mastication 

 ia rendered indispensable to the passage of the food from the mouth 

 to the stomach. This structure, by which the possibility of swallow- 

 ing any portion of unmasticated nutriment is prevented, is shown iu 

 an extraordinary formation of the velum palati uiollis, or soft i 

 In other animals this membrane generally forms an iui|ierfect float- 

 ing septum, suspended from the back part of the roof of the palate, 

 and interposed between the cavity of the mouth and pharynx, but it 

 was found in the Capybara and in some of its congeners to be much 

 more extensive in its attachment*, and different in its form and uses. 

 Ou separating the jaws the mouth appears to terminate in a nearly 

 blind pouch ; for the communication with the pharynx seems as if 

 shut by a strong membrane of a funnel shape, the concavity of which 

 recedes towards the throat. "This membrane is an exUmoV.i 

 palati attached to the whole circumference of the fauces and r 

 the tongue, and is prevented from forming a complete septum by the 

 existence of a small central circular aperture, by which a communica- 

 tion between the mouth and the pharynx is established for passage of 

 food ; so that through this small membranous funnel, or strainer (if I 

 may be allowed the expression), it is physically impossible thnt any 

 considerable portion of unmasticated nutriment should find its way, 

 by natural means, from the mouth into the alimentary canal ; ..n.| 

 from this circumstance the first process towards digestion must be 

 rendered certain and complete ; for the grosser particles of food must 

 remain in the mouth from the interposition of the membranous sieve 

 or strainer, which is thus placed between the organs of mastication 

 and those of digestion. Mr. Morgan observes that the same provision 

 for the complete mastication of all solid substances, previous to their 

 being swallowed, will be found in others of the same group, but he 

 confines his well-executed descriptions and figures of the anatomy of 

 these parts to the dissections he had made of ti /. To these 



descriptions and figures we refer the reader, offering only the conclu- 

 sion to which Mr. Morgan comes as to the use of this conformation 

 of the velum palati : this appears to him to have reference to the 

 digestive organs, and to be confined almost entirely to the process of 

 deglutition." 



rhe size of the lamina: in the posterior molar teeth, and the increase 

 in their number, indicate some approach to the pachydermatous form, 

 and we find among some of the earlier zoologists who have noticed it 

 a disposition to approximate it to the hogs. Thus Marcgrave says 

 (' Pisp,' book iii.), " Capybara inter porcos aquaticos sive fluviatilea 

 n-cipitur, quia figure et natura bimuluin porcum emulatur." lin 

 name Uydnxkirru*, Water-Hog, and Des Marchais' Cochon d'Eau, 

 point thu same way. Linnaeus, in his last edition of the ' Systema 

 Nature) ' (1 2th), arranges it under the genus Hut (litlltuz), as & J/i/iln>- 

 chirrit, and immediately after the S. Tajafu, or Peccary, next to winch 

 animal it in placed in Piso's Marcgrave. Pennant iu his ' Synopsis,' 

 calls the Capyliara, with River Hog (Wafer, in Dampier), as one of 

 the synonyms, the Thick-Nosed Tapir ; but in his ' History of Quad- 

 rupeds ' he makes it the first species of his genus Cavy, giving it a 



