BV r. Tllo.MSuN FLYNN, B.SC. 153 



In close proximity to the ends of these septa appear 

 the masses of erectile tissue. These are somewhat more 

 difTcreiitiatcd than is the case in any marsupial as yet 

 described. Each mass is caudally somewhat cylindrical, 

 tapering off to a point, and consists of large thin-walled 

 cells with muscle fibres, the whole surrounded by fibrous 

 tissue. Pursued cranially they become somewhat flat- 

 tened, and then semi-lunar surrounding tlie ends of the 

 two septa. Kelations have now been established between 

 the ventral clitoris wall and the epithelium of the cloaca. 

 This relation, in the absence of a preputium clitoridis, is 

 extremely simple, and consists of a mere approximation 

 and fusion of the two epithelia, the result being the forma- 

 tion of an epithelial septum, similar to the other septa of 

 the clitoris (Fig. 7). 



This fu.sion commences from the mid-ventral line. This 

 process of formation of relations between the clitoris and 

 cloaca differs from that of any marsupial so far described. 

 As Van den Broek points out in Halmaturus and Phas- 

 colarctos, the fusion takes place caudally through the 

 medium of a prsputium. which disappears cranially, while 

 in Didclphys, in which there is no preputium, the clitoris 

 wall being placed laterally upon the cloacal epithelium, 

 the former dwindling away, and only leaving the latter, the 

 result being the formation of a median ventral space be- 

 tween clitoris and cloaca, bounded laterally by the liui-s 

 of combination of the two. 



The points where the septa of the clitoris meet tho 

 upper surface of that organ are indicated by longitudinal 

 shallow furrows. These now invade the septa, gradually 

 converting them by the diverging of their epithelial walls 

 info deep narrow grooves. 



A glancei at Fig. 7 will show the internal structure of 

 the clitoris at this height. The organ has lost its sttper 

 ficial trilcbed structure, the two lateral Icbes having over- 

 grown the central one, which has correspondingly diminish- 

 ed in size. The latter is separated from the former by 

 incomplete septa, which aro being converted intci grooves. 

 These grooves pass ventro-laterally from the bottom of the 

 single longitudinal groove of the upper surface of the 

 clitoris, this representing the upper portion of the median 

 goptitm of other marsupials. The ventral portion of that 

 septtim remains in the section as evidence of the combina- 

 tion of two lateral portions of the clitoris. For a fair 

 distance on cither side of this latter portion of the median 



