Abnormalities of Reproductive System found in Frogs. 255 
attained their full development. In Case No, V., the interval was greater, 
but the expression of the spermatic tissue in both gonads was relatively 
late, for the Miillerian ducts are equal in every way to the oviducts of 
the adult female. 
Since the Miillerian ducts do not atrophy after they have attained 
a considerable size, even when the ovarian tissues have become completely 
replaced by spermatic, the presence of these ducts, of a female pattern, in 
an otherwise perfectly normal male, is a certain indication that the gonads 
at one phase of their development contained functioning ovarian tissue, 
and that the individual is a male whose sexual development has been indirect, 
inasmuch as there has been a phase in its life-history during which, to 
all appearances, it was a female. 
IIL.—SECONDARY SEXUAL CHARACTERS. 
In the first case these were entirely female in type; in the second they 
were male but imperfectly developed ; in the rest they were typically male, 
with one female character—the ciliated epithelium upon the peritoneum— 
in addition. In the first two cases, ovarian tissue constituted the bulk of 
_ the gonads, and this tissue, though degenerating, was sufficiently healthy 
to produce functional ova. In the rest spermatic tissue formed the greater 
part of the gonads, and such ovarian tissue as was present was pathological. 
In all cases, the spermatic tissue in the gonads was healthy and vigorously 
functional. The nature of the secondary sexual characters would seem to 
be determined, therefore, by the constitution of the gonads. Associated 
with functional ovarian tissue in the gonads are secondary sexual characters 
of the female pattern, and in conjunction with the presence of functional 
spermatic tissue in the gonads male secondary sexual characters are found. 
The expression of spermatic tissue in gonads which previously had the 
structure of ovary is associated with the assumption of male secondary 
sexual characters on the part of an individual which hitherto had shown 
secondary sexual characters of the female form. But as these characters of 
the female are mainly of a negative order, the imposition of the male characters 
cannot be regarded as difficult, for they are for the most part nothing more 
than the results of a greater degree of development locally of structures 
commonly possessed by both sexes. 3 
The ciliated epithelium upon the peritoneum once developed remains: 
it does not interfere with the assumption of the male secondary sexual 
characters. The wartiness of the skin of the back and flanks is a seasonal 
development in the functioning female at the time of the breeding-season, 
