FEMALE ORGANS OF MAKSUPIALIA. 685 



circular fibres. The lining is well organised, not deciduous : it is 

 soft, and disposed in many irregular folds, but, when these are 

 effaced, has a smooth surface : this is a distinct but delicate layer 

 with minute pores, and is connected to the muscular coat by 

 an abundant tissue, consisting of fine lamella? stretched trans- 

 versely between the muscular layer and the smooth membrane, 

 the whole being of a pulpy consistence and highly vascular, 

 especially in the impregnated state. The vaginse are lined with 

 a layer of epithelium, which is readily detachable, even from the 

 middle cul-de-sac. The inner surface of the culs-de-sac in the 

 Opossum is smooth, but in the lower part of the single cavity in 

 the Kangaroo and Potoreo it presents a reticulate structure. 

 The lining membrane in the lateral canals in all the genera is 

 disposed in regular longitudinal folds, a disposition which cha- 

 racterises the true vagina in most. In the Kangaroo, as in the 

 other Marsupialia, the lateral canals communicate with the 

 common or urethro-sexual cavity without making a projection ; 

 but at the distance of three-fourths of an inch from their termina- 

 tion there is a sudden contraction, with a small valvular projec- 

 tion in each, fig. 538, n, n. By those who consider the cul-de- 

 sac and lateral canals as a modification of the corpus uteri, these 

 projections may be regarded as severally representing an os tincae; 

 but they do not exist in the Opossums and Petaurists, in which 

 there is simply a contraction of the vaginal canals at the corre- 

 sponding part ; and in both these and the Kangaroo, the true uteri 

 open in the characteristic valvular manner, d, d, without the slight- 

 est appearance of a gradual blending with the median cul-de-sac. 



The clitoris is situated in a 

 preputial recess near the out- 

 let of the urogenital passage : 

 it is simple in those Marsu- 

 pials that have a simple 'glans 

 penis,' but is bifid in those 

 which have the glans divided : 

 and in the Opossum each 

 division of the ( glans clitori- 

 dis ' is grooved. 



The marsupial type is re- 

 peated in one of the rarer ano- 

 malies of the female organs 

 in the Human species : in 

 which not only the uterine cavities are distinct, but the ' os 

 tincaj ' of each opens into its own vagina, fig. 539. 



Double uterus and vagina, Human anomaly, ccxlvi' 



