318 



MARSUPIALIA. 



formation, and at the same time to have been 

 coincident with a completely divided uterus.* 



It is not unusual to find the vaginae of the 

 Kangaroo distended with a gelatino-mucous 

 adhesive secretion containing hard irregularly 

 shaped fibrous masses. One of these bodies, 

 which was found in the mesial cul-de-sac of 

 a Kangaroo, was described and figured by 

 Sir Everard Homef as the vertebral column 

 and occipital bone of a foetus ; and his first 

 theory of marsupial generation appears to have 

 been much influenced by this belief. Professor 

 Leuckart,J who found similar bodies in the 

 vaginal tubes of a Kangaroo, compares them to 

 a mola, or false conception, but observes that 

 there was nothing in their structure that would 

 permit him to form a conclusion that they were 

 parts of a foetus. 



In the Wombat the lining membrane of 

 the vaginal culs-de-sac is greatly increased by 

 innumerable irregular rugje and papilla, the 

 urethro- sexual canal is lined by a thick epi- 

 thelium, and its surface is broken into count- 

 less oblique rugae and coarse papillae ; the 

 surface immediately surrounding the urethral 

 orifice, which in this as in other Marsupials 

 is close to the vaginal orifices, is comparatively 

 smooth. 



The clitoris is situated in a preputial recess 

 near the outlet of the uro-genital passage : it is 

 simple in those marsupials that have a simple 

 glans penis, but is bifid in those which have 

 the glans divided : and in the Opossum each 

 division of the glans clitoridis is grooved. 



Development of the Mursupiuliu. Before 

 proceeding to detail the present received doc- 

 trine of the generation and development of the 

 Marsupialia, it may not be unprofitable to take 

 a rapid glance at the different opinions that 

 have prevailed at different periods respecting this 

 interesting and difficult part of their economy. 



The minute size of the young of the Ameri- 

 can Opossum when first received in the mar- 

 supium, their pendulous attachment to the 

 nipples, and perhaps the mode in which the 

 nipples themselves are developed, gave rise, 

 among the earlier observers, to a notion that 

 the young were originally formed by and from 

 those parts. 



And this belief was not only current then, as 

 now, among the unscientific settlers in the colo- 

 nies where the marsupial animals are common, 

 but was entertained likewise by the best in- 

 formed Naturalists of those times. Thus the 

 learned Marcgrave, in his account of the Opos- 

 sum, says, when speaking of the marsupial 

 pouch, " Heec bursa ipse uterus eat Animulh, 

 nain (ilium non habet, uti ex sectione illius coin- 

 pert ; in hue semen concipitur et cutuli forman- 

 tur." And Piso repeats the assertion more 

 strongly. " Ex reiteratis horum unimulium 

 sectionibus alium non invenimus uterum prteter 



* Dr. Purcell, Philosophical Transactions, vol. 

 Ixtv. p. 478. 



f Philos. Trans, vol. Ixxxv. p. 228. 



\ Meckel's Archiv fur Physiologic, torn. viii. 

 p. 442. 



$ Hist. Rerum Naturalium, Brasil. 1648. 



hanc biirsarn, in qua semen concipitur et catuli 

 J'orinuntur. Quos delude quinos velsenos simul 

 circumfert, mobiles, perfectos, sed depilett, udeo- 

 que. pertinaciter uberibus affixos, ut a perpetuo 

 suctu vit rivelhintur, antequam permittent.e 

 mat re ad pastum ipai egrediuntur." : 



The assertion that the young grow from the 

 nipple was again repeated in regard to the 

 Philander Opossum ( Dide Ipht/s Philander) by 

 Valentin in his History of Amboyna, and has 

 even been revived at a comparatively recent 

 period. f Some glimpses of the truth were ob- 

 tained, however, before the time of the authors 

 who have been last quoted. Hernandez, for 

 example, speaks of the generation of the 

 Opossum almost in the same words in which 

 CuvierJ sums up the then existing know- 

 ledge of the subject in the second edition of 

 his ' Regne Animal.' " Quaternos, quinosve 

 parit catulos, quos utero conceptos, editosque in 

 lucem, alvi capacitate quadam, dum udhuc par- 

 vuli sunt, claudit ac servat." And Mafiieius 

 more particularly describes the attachment of 

 the young to the nipple. " Illud autem inirum 

 in Cerigonibus" (Opossums) "ex ejusalvo duae 

 dependent veluti manticae, in iis catulos cir- 

 cumfert, et quidem adeo pertinaciter suoquem- 

 que uberi affixes, ut a perpetuo suctu non 

 avellantur, antequam ad pastum ipsi per se 

 progredi valeant."|| 



Nevertheless, as the uterine gestation is here 

 simply alluded to without any detailed obser- 

 vations in proof of it, the assertion was compara- 

 tively of little value in a scientific point of view; 

 and the gemmiparous theory, supported by 

 Marcgrave and Piso, seems to have been pre- 

 valent at the time when Dr. Tyson first turned 

 his attention to this subject. 



The discovery of the true uterus, recorded 

 by that learned and accurate anatomist in the 

 20th volume of the Philosophical Transactions, 

 p. 105, was the first step towards a correct 

 theory of the generation of the marsupial ani- 

 mals. It necessarily caused him to reject the 

 gemmiparous theory, but, as often happens in 

 such cases, Tyson was led into the opposite or 

 sceptical extreme ; and he was also induced to 

 doubt the really accurate statements of Her- 



* De Indiae utriusque Re Natural! et Medica, 

 lib. v. c. 24, 1658. 



t See Geoff. St. Hilaire, in the Journal Comple- 

 mentaire du Diet, des Sciences Medicales, torn. iii. 

 p. 193 (1819) : " Si les animaux a bourse naissent 

 aux tetines de leur mere." 



J " La premiere de toutes leurs particularites 

 est la production prematuree de leurs petits, qui 

 naissent daus un etat de developpement a peine 

 comparable a celui auquel des foetus ordinaires par- 

 viennent quelques jours apres la conception. In- 

 capables de mouvement, montrant a peine des 

 germes de membres et d'autres organes exterieures, 

 ces petits s'attachent aux mamelles de leur mere et 

 y restent fixe* jusqu'ace qu'ils se soient developpes 

 au degre auquels les animaux naissont ordinaire- 

 ment. Presque toujours la peau de 1'abdomen est 

 di?posee en forme de poche autour de ce mamelles, 

 et ces petits si impariaits y sont preserves, comme 

 dans une seconde matrice." Recne Animal, 1829, 

 vol. i. p. 172. 



Hist. Mexican, lib. ix. p. 330. 



|| Joh. Petr. Maffeius, Hist. Indica. 



