8 



K. A N G U II O O. 



of the tail, would not exceed one inch two lines. 

 A lineal' longitudinal mark of the umbilicus was 

 apparent. 



" It has been ascertained by Barton that the young 

 of the opossum, immediately after birth, are in a much 

 more imperfect condition than that above described in 

 the kangaroo, being merely gelatinous corpuscles, com- 

 parable to a Medusa; but the observations of Dr. 

 Rengger on an opossum (Didelp/ris fizaree. Temrninck), 

 nearly allied to the Virginian species (D, Virginiana, 

 Cuvier), accord, as to the condition of the new-born 

 foetus, with what we have now been able to ascertain 

 with accuracy is the condition of the new-born 

 kanguroo. 



" Oct. 9. I again examined the pouch ; the young 

 one was evidently grown, and respired vigorously. I 

 determined to detach it from the nipple for the fol- 

 lowing reasons : 1st, to decide the nature of the con- 

 nexion between the foetus and nipple ; 2nd, to ascer- 

 tain, if possible, the nature of the mammary secretion 

 at that period ; 3rd, to try whether so small a foetus 

 would manifest any thing like voluntary action to re- 

 gain the nipple ; and lastly, to observe the actions of 

 the parent herself to effect the same purpose, as we 

 might presume they would be instinctively analogous 

 to those by means of which the foetus was originally 

 applied to the nipple, supposing that to take place 

 through the agency of the mother. 



" An organic connexion by vessels between the 

 mammary foetus and the nipple being a necessary 

 consequence of the truth of Dr. Barton's assertion, as 

 to the condition of the product of generation at uterine 

 birth, this has been much insisted upon ; a discharge 

 of blood has been described as a concomitant of 

 marsupial birth ; and even the anastomoses of the 

 maternal vessels, with those of the foetus, have been 

 speculated upon (see Mem. de Museum, torn, ix., p. 

 393). 



" The dissection of the mammary foetus of the 

 kanguroo by Mr. Hunter, showing the relation of the 

 nipple to its tongue and mouth, the passage of the 

 larynx into the posterior nares, the absence of the 

 uracus and umbilical vessels, &c., tended indeed to 

 disprove the theory of the vascular connexion ; and 

 the observations of Mr. Morgan and Mr. Collie, with 

 the testimony of Joseph Fuller, were completely sub- 

 versive of it. Nevertheless it was desirable to have 

 ocular demonstration of the real state of the facts at 

 this early period of the young animal's existence. 



" It was removed from the nipple without the 

 slightest trace of laceration of continuous vessels, or 

 of any kind of connecting substance ; but it adhered 

 more firmly than I had been led to expect from 

 Fuller. After it was detached, a minute drop of 

 serous milk appeared on pressure at the point of the 

 nipple ; this was the smallest part of the nipple, and 

 was not swollen or clavate ; about half a line had 

 entered the mouth of the foetus. 



" The young one moved its extremities vigorously 

 after being detached, but made no effort to apply its 

 legs to the fur or skin of the mother so as to creep 

 along ; it seemed perfectly helpless. It was depo- 

 sited at the bottom of the pouch, and the mother was 

 liberated and carefully watched. She immediately 

 showed symptoms of uneasiness, stooping down to 

 lick the orifice of the vagina, which she could easily 

 reach, and scratching the exterior of the pouch with 

 her fore paws. At length she grasped the sides of 

 the opening of the marsupium with her fore paws, 



and drawing them apart, just as one would open a 

 bag, she thrust her head into the cavity as far as her 

 eyes, and could be seen moving it about in different 

 directions. During this act she rested on her tripod, 

 formed by the tarsi and tail. She occasionally lay 

 down, but in that posture never meddled with the 

 pouch; when stimulated to do so, she immediately 

 rose, and repeated the process of drawing open her 

 pouch and inserting therein her muz/le, which she 

 sometimes kept in for half a minute at a time. I 

 never observed her put her fore legs, or either of 

 them, into the pouch ; these were invariably employed 

 to widen the orifice, or in scratching the exterior. 

 When she withdrew her head, she generally concluded 

 by licking the orifice of the pouch and swallowing 

 the secretion. 



" After repeating the above act of insertion at least 

 a dozen times, she lay down, and seemed at ease. 

 When she had rested quietly about a quarter of an 

 hour, we examined her again, and found thi> young 

 one at the bottom of the pouch, but within two 

 inches of the nipple. It was moving its extremities, 

 and respiring as vigorously as before. I attempted 

 to replace it on the nipple, but without success ; it 

 was therefore left in the pouch, and the mother was 

 released. 



" My engagements prevented me from visiting the 

 gardens the day but one after this examination, when 

 at ten A.M. I examined the marsupiurn, but the foetus 

 was gone. We searched very carefully every portion 

 of the litter, &c., in the hope of finding it, but with- 

 out success. I concluded, therefore, that the foetus 

 had died, and that the mother had probably eaten it. 



" From what I observed of the mother after the 

 separation of the foetus, I should conclude that partu- 

 rition takes place in the erect and not in the recum- 

 bent posture ; and on perceiving the ease with which 

 she can reach with her mouth the orifices of the 

 vagina and pouch, a means adequate to the removal 

 of the young from the one to the other became ob- 

 vious. I should suppose the fore paws not to be used 

 for the transmission of the foetus, but to keep open 

 the pouch ready for its reception, v, hile the mouth 

 would be the means by which it would be deposited 

 therein, and perhaps held over a nipple till the 

 mother felt the sensitive extremity grasped by the 

 young one. 



" This mode of removal is consistent with analogy. 

 Cats, dogs, and mice transport their young by the 

 mouth. 



" I ought perhaps to have forborne this hypothesis 

 when an opportunity of actually observing the pro- 

 cess may so soon be afforded ; but it was suggested 

 by observing the actions of the mother after an arti- 

 ficial separation of the fcetus from the nipple, and 

 accords with the phenomena better, I think, than any 

 that have been previously proposed. There is no 

 internal passage ; there is no power of bringing the 

 mouth of the vagina in contact with that of the pouch, 

 either in the living or dead kangaroo, without lesion 

 of the parts ; the fore paws could not so effectually 

 protect the embryo from the external hair on the lips, 

 nor so safely ensure its passage ; and the young one 

 itself did not by any of its actions give the idea of its 

 having the power of creeping up thfe fur along the 

 pouch lo the nipple. 



" Where, however, the structure of the pouch, as 

 in Permnek's, and some South American opossums, is 

 different, the mother's aid may be less necessary ; but 



