1886. } MR. J. B. SUTTON ON ATAVISM. 553 
pocularis, utriculus, or uterus masculinus. Usually it is nearly half 
an inch long, and opens by a narrow slit in the middle of the caput 
gallinaginis. It is lined by mucous membrane continuous with that 
of the urethra, and covered by stratified epithelium. Some small 
tubular glands open on the free surface of the mucous membrane. 
This utriculus is of great interest morphologically, as it represents 
in the male a persistent portion of the confluent segment of the 
Miillerian ducts. Weber regarded it as corresponding with the 
uterus, but Leuckart showed that a part of it must be looked upon 
as representing the vagina. 
My observations induce me to regard the prostate as a suppressed 
uterus, the fibro-muscular tissue representing the matricial walls, the 
follicles correspond to the utricular glands, and the utriculus is 
identical with the cervix uteri and that portion of the vagina 
immediately adjacent. 
The evidence in support of this view will now be put before the 
reader. In order to render every detail in clear light, we must refer 
briefly to the fundamental structures concerned in forming a func- 
tional uterus. 
In the Lizard, in common with the majority of the Sauropsida, 
the ova are conveyed to the exterior by two muscular tubes lined 
with mucous membrane, known as oviducts. The eggs, when they 
escape from the ovaries, are received by the dilated end of the 
oviduct, known as the infundibulum, and quickly passed onwards ; 
they receive at the commencement of the journey a coating of albumen. 
Pushed on by the contortions of the tube, they arrive at the third 
or uterine portion. Here they receive a coating of calcareous matter 
known as the shell, and are then ready for expulsion. In these 
oviducts, with their mucous membranes and glands, we have the 
fundamental condition of the ducts which in the human embryo 
conspire to form the uterus with its Fallopian tubes and vagina. 
In order to clearly describe the manner in which the Fallopian 
tubes, uterus, and vagina are formed from the Miillerian ducts of 
opposite sides, each duct may be conceived as made up of three 
parts :-— 
The upper third becomes the Fallopian tube; the funnel-shaped 
and usually fimbriated extremity communicates with the peritoneal 
cavity. The middle portions of the ducts fuse together, and form the 
fundus, body, and neck of the uterus, whilst the lower thirds of the 
Miillerian ducts form a vagina. Such is the commonest arrange- 
ment. 
On comparing the parts of this compound organ with the Lizard’s 
oviduct, it becomes evident that the infundibulum and albumen 
segment in the bird represent the Mammalian Fallopian tube, the 
second or uterine portion corresponding with the uterus and vagina 
of Eutheria. 
On tracing the homologies closer, we find that the portion ot 
the bird’s oviduct concerned in secreting albumen corresponds with 
that portion of the Miillerian duct which forms the fundus and body 
of .the uterus; and the utricular glands, which are coucerned in 
