196 



MAMMALIA. 



is no approximation to the articulation of the quad- 

 ruped reptiles, which, whether they more fast or 

 alow, always have the joints of the legs turned in a 

 very peculiar manner, so as never to be mistaken for 

 animals of any other class. 



There is another circumstance which probably 

 tended to mislead those naturalists who looked too 

 exclusively to the facts immediately before them, and 

 the analogies of the mammalia, without due attention 

 to those of the marsupial ones. It was not then 

 known that the mammae or teats of these animals are 

 deciduous, or that they shrivel, the apex dropping off 

 and the glands being completely absorbed, when not 

 required ; and it is highly probable that no two young 

 ones are ever nursed upon the same teat of a mother, 

 that is to say, in successive generations, whether the 

 one generation follow the other ere that other is yet 

 completely formed, o*whether years, or longer inter- 

 vals of time, may come in between them. This being 

 the case, it is evident that no conclusion could be 

 drawn from the total absence of teats in the female 

 ornithorhynchus, unless these animals should be found 

 accompanied by young, and without this apparatus. 

 The number of these animals are so few, and their 

 habits and modes of life are so difficult to be observed, 

 that though an individual now and then was occasi- 

 onally found, the searchers for them did not meet 

 with a gravid female, or a female accompanied by 

 very young offspring. This, of course, left the case 

 open to conjecture ; and as ornithorhynchi have been 

 seen about some of the pools of the Australian 

 streams, and eggs found in the banks soon afterwards, 

 without any animal being observed to which those 

 eggs could belong, there was the evidence of juxta- 

 position in favour of their being the esrgs of the orni- 

 thorhynchus. This same juxta-position is a very 

 treacherous argument in natural history ; and if we 

 obtain nothing from analogy to bear it out, and espe- 

 cially if we have anything from analogy positively 

 bearing against it, we cannot use it with anything 

 like safety ; and this turned out to be very remarkably 

 the case with the supposed eggs of the ornithorhyn- 

 chus. More careful inquiry succeeded in obtaining the 

 young with the mandibles so short as to form a mouth 

 capable of sucking, though one of very singular 

 shape ; and though the evidence has not yet been 

 carried that length, it is by no means impossible that, 

 at an earlier stage the young ornithorhynchi may be 

 so formed as to be able to adhere to the teats of the 

 mother, in the same manner as the other marsupial 

 animals. The following is a portion of the account 

 transmitted to the Zoological Society of London, from 

 the Honourable Lieutenant Maule, who, in common 

 with very many officers both of the British army and 

 the British navy, placed on foreign stations, is now 

 cultivating natural history with equal assiduity and 

 success. We quote from the proceedings of the 

 Society's Committee of Science, to which committee 

 the information was first communicated. " During 

 the spring of 1831," writes Lieut. Maule, " being de- 

 tached in the interior of New South Wales, I was at 

 some pains to discover the truths of the generally ac- 

 cepted belief, namely, that the female Platypus lays 

 eggs and suckles its young. 



" By the care of a soldier of the 39th Regiment, 

 who was stationed on a post at the Fish River, a 

 mountain stream abounding with Platypi, several 

 nests of this shy and extraordinary animal were dis- 

 covered. 



" The Platypus burrows in the banks of rivers, 

 choosing generally a spot where the water is deep 

 and sluggish, and the bank precipitous and covered 

 with reeds, or overhung by trees. Considerably be- 

 neath the level of the stream's surface is the main 

 entrance to a narrow passage which leads directly 

 into the bank, bearing away from the river (at a 

 right angle to it), and gradually rising above its 

 highest water-mark. At the distance of some few 

 yards from the river's edge, this passage branches into 

 two others, which, describing each a circular course 

 to the right and left, unite again in the nest itself, 

 which is a roomy excavation, lined with leaves and 

 moss, and situated seldom more than twelve yards 

 from the water, or less than two feet beneath the sur- 

 face of the earth. Several of these nests were, with 

 considerable labour and difficulty, discovered. No 

 eggs were found in a perfect state, but pieces of a 

 substance resembling egg-shell were picked up out of 

 the debris of the nest. In the insides of several 

 female Platypi which were shot, eggs were found of 

 the size of a large musket-ball and downwards, imper- 

 fectly formed however ; i. e. without the hard outer 

 shell, which prevented their preservation." 



The eggs, without any shells which Lieut. Maule 

 describes as having been met with in female ornitho- 

 rhynchi were no doubt the young, in a state probably 

 sufficiently far advanced for being ready for their ex- 

 ternal destination ; but it does not appear that there 

 is any thing which can decidedly connect the sub- 

 stance resembling egg-shell either with the mother or 

 with the young. 



It must be borne in mind that the question here 

 is not whether the primary rudiment of the ornitho- 

 rhynchus is or is not an egg ; because the rudiment of 

 every known animal is an egg ; and the question is 

 only as to the state of development in which this 

 egg is when it leaves the body of the parent animal. 

 In the true mammalia the maturing is internal ; and 

 though the young are in different degrees of perfec- 

 tion at their birth, according to the nature of the 

 species, they are always sufficiently developed tor 

 being capable of sucking the mother by means of the 

 mouth. In the marsupial animals it is probable that 

 there are also differences of development in the young 

 of different species, when they leave the internal 

 uterus ; but they leave that uterus without any distinct 

 development of parts, and therefore without the capa- 

 city of performing any of what are called the 

 voluntary functions of animals. They have no mouth 

 formed, although they have a means of attachment to 

 the nipple ; and until they have a mouth, and can 

 quit and regain the nipple at pleasure, it is highly 

 probable that the nourishment they receive from that 

 organ is not milk suited for the purpose of ordinary 

 digestion, and requiring the action of the air in breata- 

 ing before it is fit for the purposes of life : but that it 

 is a fluid derived immediately from the unchanged 

 arterial blood, and therefore requiring no more breath- 

 ing or action of the air in the young which receives 

 it, than the nourishment of the true mammalia requires 

 while they are in the uterus. Indeed the arterial 

 structure of the hinder parts of these animals is such, 

 that the same supply of arterial blood may go either 

 to the uterus or the teats, or that it may go in part to 

 both at the same time. 



We must therefore consider the marsupial teats as 

 having somewhat of a placental character, as long as 

 the young adhere to them, and are formless. It should 



