Bauhaus-Universität Weimar

Titel:
The Cyclopaedia of Anatomy and Physiology, vol. 3: Ins-Pla
Person:
Todd, Robert Bentley
PURL:
https://digitalesammlungen.uni-weimar.de/viewer/image/lit29464/326/
MARSUPIALIA. 
formation, and at the same time to have been 
coincident with a completely divided uterus.* 
It is not unusual to find the vaginæ 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 Ilomef as the vertebral column 
and occipital bone of a fœtus ; 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 fœtus. 
In the Wombat the lining membrane of 
the vaginal culs-de-sac is greatly increased by 
innumerable irregular rugæ and papillæ, the 
urethro-sexual canal is lined by a thick epi¬ 
thelium, and its surface is broken into count¬ 
less oblique rugæ and coarse papillæ; the 
surface immediately surrounding the urethral 
orifice, which in this as in other Marsupials 
is close to the vaginal orifices, is comparatively 
smooth. 3 
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 Marsupiulia.—Before 
proceeding to detail the present received doc¬ 
trine of the generation and development of the 
Marsupialiâ, 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, “ Hœc bursa ipse uterus est Animalis, 
nam alium non habet, uti ex sectione illius com- 
peri ; in hac semen concipitur et catuliforman- 
tur.” § And Piso repeats the assertion more 
strongly. “ Ex reiteratis horum animalium 
sectionibus alium non invenimus uterum prater 
* Dr. Purcell, Philosophical Transactions, vol. 
lxiv. p. 478. 
f Philos. Trans, vol. lxxxv. p. 228. 
t Meckel’s Archiv fur Physiologie, tom. viii. 
p. 442. 
§ Hist. Rerum Naturalium, Brasil. 1648. 
hanc bursam, in qua semen concipitur et catuli 
formantur. Quos deinde quinos velsenos simul 
circumfert, mobiles, perfectos, sed depiles, adeo- 
que pertinaciter überibus affixos, ut a perpetuo 
suctu vix avellantur, antequam permittente 
matre ad pastum ipsi egrediantur.” * 
The assertion that the young 'grow from the 
nipple was again repeated in regard to the 
Philander Opossum (Didelphys 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 ‘ Règne Animal.’ “ Quaternos, quinosve 
parit catulos, quos utero conceptos, editosque in 
lucem, alvi capacitate quâdam, dum adhuc par- 
vuli sunt, claudit ac servat.Ӥ And Maffeius 
more particularly describes the attachment of 
the young to the nipple. “ Illud autem mirum 
in Cerigonibus” (Opossums) “ ex ejus alvo duæ 
dependent veluti manticæ, in iis catulos cir¬ 
cumfert, et quidem adeo pertinaciter suoquem- 
que uberi affixos, 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 Indiæ utriusque Re Naturali et Medicâ, 
lib. v. c. 24, 1658. 
t See Geoff. St. Hilaire, in the Journal Comple¬ 
mentaire du Diet, des Sciences Médicales, tom. iii. 
p. 193 (1819) : “ Si les animaux à bourse naissent 
aux tétines de leur mère.” 
f “ La première de toutes leurs particularités 
est la production prématurée de leurs petits, qui 
naissent dans un état de développement à peine 
comparable à celui auquel des fœtus ordinaires par¬ 
viennent quelques jours après la conception. In¬ 
capables de mouvement, montrant à peine des 
germes de membres et d’autres organes extérieures, 
ces petits s’attachent aux mamelles de leur mère et 
y restent fixés jusqu’àce qu’ils se soient développés 
au degré auquels les animaux naissent ordinaire¬ 
ment. Presque toujours la peau de l’abdomen est 
disposée en forme de poche autour de ces mamelles, 
et ces petits si imparfaits y sont préservés, comme 
dans une seconde matrice.” Règne Animal, 1829, 
vol. i. p. 172. 
§ Hist. Mexican, lib. ix. p. 330. 
Il Joh. Petr. Maffeius, Hist. Indica.
        

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