108 Prof. Owen on the Echidna Hystrix. [Mar. 2 } 



ovarium ; the largest with a diameter of 1^ line, the least of the five with 

 a diameter of rather less than 1 line. Besides these there was a flattened 

 ovisac, 2^ lines in length, and 2 lines in opposite diameters, of a flattened 

 pyriform shape, with a somewhat wrinkled exterior, attached hy the base, 

 with the apex slightly tumid, and showing a trace of a fine cicatrix. This 

 was an ovisac from which an ovarian ovum had been discharged. 



The oviducal branch of the ovarian ligament passes, as in the Orni- 

 thorhynchus, to the outer angle of the wide oviducal slit or aperture, 

 which occupies or forms the margin of the ovarian pouch opposite to that 

 to which the ovary is attached. The ligament spreads upon the inner 

 wall of the infundibular part of the oviduct, and rejoins the ovarian 

 division of the ligament to be continued along the oviduct, puckering up 

 its short convolutions into a small compass. The " fallopian" aperture of 

 the infundibulum is a longitudinal slit of 9 lines in length, with a delicate 

 membranous border extending about a line beyond where the muscular 

 and mucous tunics of the oviduct make the thin wall of the infundibulum 

 opaque, its transparency against a dark ground contrasting with the 

 opaque beginning of the proper tunics of the oviduct, which nevertheless 

 are here very thin. No part of this delicate free margin is produced into 

 fimbrise ; in this respect Echidna accords with 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. This is 

 about 2 inches long, and 6 lines in diameter. It commences by a short 

 well-marked bend, convex outwards, and then proceeds nearly straight, the 

 pair converging to the urogenital compartment, slightly contracting at its 

 termination, which projects, as an " os tincae," into the side of the fundus 

 of that division of the cloaca. 



The tunics of the uterus are, externally, the peritoneum, which is 

 attached by a lax cellulosity to the " tunica propria ; " this, with its 

 fibrous or muscular layer, is thin, not exceeding -i-th of a line in the pre- 

 sent specimen. The inner layer of the uterine wall is the thickest, and 

 chiefly composes it, consisting of fine lamellae stretched transversely 

 between the fibrous layer and the fine smooth lining membrane, the whole 

 being of a pulpy consistence, and doubtless in the recent animal highly 

 vascular, especially in the impregnated state. The lining membrane was 

 devoid of any trace of vascular connexion with the membranes of an ovum 

 or foetus, and was thrown into delicate irregular rugae, which assumed the 

 longitudinal direction at the " cervix" or contracted terminal part of the 

 uterus. The orifice on the "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 circul ar orifice cf the ureter. 



The right ovarium was proportionally more developed and larger than 



