254 Proceedings of the Royal Physical Society. 
It would seem that if the appearance of the spermatic tissue is 
relatively late then, in the presence of ovarian tissue of considerable 
amount and functional capacity, these ducts attain the condition character- 
istic of the oviducts of the adult female. If spermatic tissue then 
becomes expressed and the ovarian tissues removed in consequence, the 
Miillerian ducts, having overstepped the degree of development typical of 
the male, are not affected by the transformation of the gonads and do~ 
not atrophy though obviously useless.. This is the case also with the 
ciliated epithelium found upon the peritoneum, for once developed it 
does not atrophy. 
On the other hand, if the expression of the spermatic tissue is relatively 
early, it will occur before the Miillerian ducts have attained their full 
development in the presence of considerable amounts of functioning ovarian 
tissue, Since the appearance of the spermatic tissue is associated with the 
cessation of the activities of the ovaries, for these degenerate almost at once, 
and the further development of the Miillerian ducts is thereby prohibited. 
The degree of development of these ducts is some indication, therefore, of 
the relative time when the transformation of the gonads began. 3 
Further, the Millerian ducts may be of unequal size. It would seem 
that the degree of development of a duct is determined, to some extent, 
by the degree of the functional activity of the ovary of the same side. For 
example, in Kent’s case (Fig. 7), the conditions found suggest that the 
transformation first began in the left gonad and at a relatively early stage of 
sexual development. The left Mullerian duct is only feebly developed since 
the ovarian tissues were destroyed before they had attained any considerable 
degree of development. In the case of the right gonad, the appearance of 
the spermatic tissue was relatively later and did not occur in time to prevent 
the action of the ovarian internal secretion. The condition also suggests 
that in these cases in which the expression of the spermatic tissue is 
primarily unilateral, the destruction of the ovarian tissues of the opposite 
gonad is not so rapidly effected as that of those of the ovary-portion of an 
ovo-testis. 
In Huxley’s second case, the conditions are very similar (Fig. 16). In 
Cases Nos. I. and II., the expression of the spermatic tissue was primarily 
unilateral, and occurred at so late a stage in the development of the individual 
that the Miillerian ducts had already attained their full development. In 
Case No. IV., the expression of the spermatic tissue was very nearly 
synchronous in the two gonads, and occurred early; in Case No. VIL, 
there was an interval between the appearance of the spermatic tissue in 
the two gonads, but in both it appeared before the Miillerian ducts had 
