380 



E C H I M Y S. 



orifice for their transmission are larger than the 

 orifices of their ducts, which is the reverse of what is 

 observed in ornithorhynchus : this, however, may not 

 be the case in the fully developed gland. The areoUe 

 are also slightly raised above the surrounding inte- 

 gument, but there is no vascular rete or erectile tissue 

 discoverable at these parts. The lactiferous ducts, 

 before penetrating the corium, pass between the fibres 

 of a dense panniculus carnosus which is here, as in 

 ornithorhynchus, interposed between the glands and 

 the integument. The nun\ber of the ducts is about 

 sixty. The lobules of the gland are proportionally 

 shorter and broader. Their texture under the lens 

 appears the same as ornithorhynchus, that is to say, 

 minutely cellular, and in neither instance consisting of 

 simple caeca or elongated follicles. From their small 

 size in the Echidna they could not be injected. 



" The smallest size which these glands have pre- 

 sented in Ornithorhynchus is about one-third larger than 

 those in Echidna, now exhibited; in this state, the ovary 

 and uterine tubes were small, and apparently in a 

 state of quiescence. When the ovary is fully deve- 

 loped, and the uterine tubes correspondently enlarged, 

 the mammary glands are about two inches in the long, 

 and one in the short diameter. When the ovary is 

 found large, but flaccid, and apparently after having 

 shed its contents, and when the uterine tubes are 

 still large, then the mammary glands exhibit their 

 greatest development, equalling five inches in the 

 long, and three inches in the short diameter, and 

 being nearly half an inch in thickness. In this state, 

 they may be readily injected ; when the lactiferous 

 ducts, to the number of about one hundred and fifty t 

 are seen to terminate in a small oval areola on the 

 external surface, not on any raised eminence, but on 

 the level integument, from which the bases grow as 

 freely as in the surrounding parts. Nevertheless, 

 from the glands being confined to the female, and 

 exhibiting, by their variation of size, that their func- 

 tion is temporary ; and as the period of theirgreatest en- 

 largement is shown, by the state of the uterine organs, 

 to be subsequent to the development and expulsion 

 of the foetus ; they must be regarded as being true 

 mammary glands destined to provide nourishment for 

 the newly-born animal. The peculiar development 

 of the panniculus carnosus over the ventral region, 

 both in Echidna and Ornithorynchm, will assist in 

 explaining the mode in which the lacteal secretion is 

 conveyed from the parent to the offspring. The 

 gland lying between this muscle and the expanded 

 cartilages of the ribs and the marsupial bones, is sub- 

 ject to compression, and the young animal need only 

 apply its soft and flexible lips to the areola in order 

 to receive the secretion." 



The characters are, the muzzle or bill very slender, 

 terminated by a small mouth, with the tongue exten- 

 sile, like those of those of the ant-eaters and pango- 

 lins ; and the probability is that, like those creatures, 

 they feed chiefly upon ants and other small ground 

 animals, which are exceeding^ numerous in Australia. 

 They are without teeth in the jaws, which instead are 

 terminated by the horny mandibles already men- 

 tioned ; but in the palate they have nunierous rows of 

 little spines. Their feet are very short, and each 

 furnished with five claws, very long, strong, and well 

 adapted for digging. The whole upper part of the 

 body is covered with spines, bearing some resem- 

 blance to those of the hedgehog ; and when they are 

 apprehensive of danger, and unable to escape from it 



by burrowing, they can erect their spines, and roll 

 themselves in a ball like the hedgehogs. Those 

 spines are not their entire covering, but are mixed 

 with hairs, and on the lower part of the body there 

 are hairs of a spinous form, which are tubular and 

 tapering to the points. Their shoulders are so formed 

 as that the foot can work something after the fashion 

 of the wings of birds ; and the articulations of the 

 shoulders are kept apart anteriorly by a sort of furcal 

 bone. In this respect their shoulders have a resem- 

 blance both to the lizard tribe, and to the smaller 

 mammalia which burrow in the ground. There are 

 two species, of which the habits so far as known do 

 not differ, the chief difference being in the covering. 



SPINOUS ECHIDNA (E. hy striae). All covered over 

 with strong spines on the' upper part, varying from 

 an inch and a half in length, white for the greater 

 part of their length, but the points black. Those on 

 the tail are erected, but those on the upper part of 

 the body are sloping, unless when the animal is 

 excited. Among the bases of the spines, there is a 

 quantity of coarse short hair of a reddish colour. 

 The head and under part of the body are also covered 

 with short coarse hairs. This species is about the 

 same size as the common hedgehog ; it has been 

 found only in New Holland. 



BKISTLY ECHIDNA ( E. setosa}. This species is a 

 little larger than the former, has the claws shorter, 

 but more hooked and pointed. The whole body is 

 covered with produced bristly hair of a maroon 

 coliur, which conceals the spines, and this thick co- 

 ver ng reaches as far forward as the eyes. The muzzle 

 is black and naked, all the under part is covered with 

 stiff white hairs, bearing some resemblance to hogs' 

 bristles. This species has been found in Van Die- 

 men's Land, and also in the islands which are situated 

 in Bass's Strait, between that island and New Holland. 



ECHIMYS spinous rats. A genus of rodent 

 mammalia, bearing a very considerable resemblance 

 to the common rats in their size, their general form, 

 and several other particulars, but differing entirely 

 from them in the nature of their covering, their haunts, 

 and their geographical distribution. 



All the species of this genus, which are pretty 

 numerous, and of which we shall give a short account, 

 are natives of the central and northern parts of Ame- 

 rica. They are inhabitants of the woods, nestling in 

 the herbage, at the roots of trees, and not coming 

 about houses, or on the cultivated grounds. Their 

 food is understood to consist chiefly of fallen plants 

 and other vegetable matters. 



They resemble the rat, properly so called, in the 

 oblong form of their heads. They have four grinders 

 in each side of both jaws, but they are differently 

 formed ; those in the upper have ridges of enamel, 

 arranged in the form of the letter V, while in the 

 under jaw they have one simple lamina, and a plaited 

 one. In the upper jaw all these four teeth are nearly 

 of equal size, but in the under jaw the front one is 

 nearly equal to all the other three. The distinguishing 

 characters of the skull are, that the suborbital bone is 

 very much enlarged, that there is no temporal fossa, 

 and that the ridge of the frontal bone is very much 

 produced on each side, so as to afford an ample 

 enfoncement to the eye. The body is elongated like 

 that of the true rats. The tail varies in length in the 

 different species, but it is always round in its section, 

 and often covered with scales, and in one species only 

 it is covered with very fine hair. On the forefeet in 



