AND MAMMAEY ECETTTS OF THE ECHIDNA HYSTEIX. 
679 
Echidna accords with the Ornithorhynchus, and equally manifests the character by 
which the Monotremes differ from the Marsupials*. 
The infundibular dilatation suddenly contracts about an inch from the opening into a 
“ fallopian tube,” about a line in diameter, which is puckered up into four or five short 
close coils. The oviduct, after a slight contraction, suddenly expands into the uterus 
(ib. d ). This is about 2 inches long, and appears to have been about 6 lines in diameter, 
before being cut open. It commences by a short well-marked band, convex outwards, 
and then proceeds nearly straight, the pair converging to the urogenital compartment, 
slightly contracting at its termination, which projects, as an “ os tincse ” (ib. s'), into the 
side of the fundus of that division of the cloaca. 
The tunics of the uterus are, externally, the peritoneum (ib. fig. 2, a), which is attached 
by a lax cellulosity to the “ tunica propria” (b ) ; this, with its fibrous or muscular layer, 
is thin, not exceeding ^th of a line in the present specimen. The inner layer of the 
uterine wall ( c ) is the thickest, and chiefly composes it, consisting of delicate vascular 
lamellae stretched transversely between the fibrous layer and the fine smooth lining 
membrane ( d ), the whole being of a pulpy consistence, and doubtless in the recent 
animal highly vascular, especially in the impregnated state. 
The lining membrane was thrown into delicate irregular rugae, which assumed the 
longitudinal direction at the “cervix” or contracted terminal part of the uterus. It is 
laid open in the left uterus ; a style (s) is passed through it in the right uterus. 
The orifice in the 44 os tincae” was a puckered slit, about a line in extent ; below it, on 
a produced or papillose part of the prominence, was the small circular orifice of the 
ureter; a fine hair is passed through each of these tubes in fig. 1, u, Plate XLI. 
The right ovarium (o'), was proportionally more developed and larger than in the 
Ornithorhynchus paradoxus \ three ovisacs were enlarged and attached to the stroma, 
as in the left ovarium ; and there was also a compressed ovisac (g), similar in size and 
shape to that in the left side, and exhibiting an apical cicatrix; whence it is to be 
inferred that, in this instance, the right as well as the left ovarium had furnished an 
impregnated ovum ; and the near equality of size and close similarity of structure and 
condition of the right oviduct and uterus equally evinced that they had participated in 
the last operations of the season of generation. 
Figure 2 gives a magnified view of the structure of the right uterine walls, as seen in 
transverse section. 
The urinary bladder (r), opened into the middle of the fundus of the urogenital com- 
partment, as indicated by the stylet (r, fig. 1, Plate XLI.), the uterine orifices intervening 
between the vesicular one and those of the ureters, as in the Ornithorhynchus paradoxus. 
* See Philosophical Transactions, 1834, Plate YI. fig. 1- — “fimbriae” of Kangaroo” ; and art. Marsupialia, 
Cyclop, of Anatomy and Physiology, vol. iii. fig. 137, “fimbriae” still more remarkably developed in the 
Wombat ( Phascolomys ). The absence of these fimbriae, and the resemblance of the true abdominal orifice of 
the oviduct to that of the ovarian pouch, or to an ordinary duplication of membrane, appear to have prevented 
its recognition by Drs. M. and R. 
5 b 2 
