420 Royal Society .— 



The marsupial pouches are two in number, about 1| inch apart, 

 each with the aperture longitudinal and towards the medial line, on 

 the ventral integument, half an inch in depth and two-thirds of an 

 inch in length. The young Echidna, about one inch in length in a 

 straight line, could be received in a bent posture into the pouch, and 

 might cling to the fine hairs of that part by its claws ; but there was 

 no trace of nipple. Each mammary gland terminates by numerous 

 ducts upon the fundus of the corresponding pouch. 



The left ovarium, as in the Ornithorhynchus •paradoxus, was 

 of an oblong flattened form, developed from the posterior division of 

 the ovarian ligament and corresponding wall of the ovarian capsule ; 

 it consisted of a rather lax stroma, invested by a smooth, thin, firm 

 " tunica propria," which glistens where stretched over the enlarged 

 ovisacs. Of these there were five, of a spherical form, most of them 

 suspended by a contracted part of their periphery, not stretched 

 into a pedicle, to the rest of the ovarium — the largest with a dia- 

 meter of 1-J 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 by 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 

 Ornithorhynchus, 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 ovi- 

 duct, and rejoins the ovarian division of the ligament to be con- 

 tinued 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 fimbriae ; 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, 



