THE FEMALE REPRODUCTIVE ORGANS 289 
marsupials, another group is like the monotremes, a 
third shows a complete fusion with a single cordiform 
uterine body, while the last resembles somewhat the 
first, but the uterine divisions are bound together and 
the vagina is divided only half way down. The Insec- 
tivora occupy a transitional position resembling higher 
and lower groups in having a long uterovaginal canal, 
without distinct cervix, extending upward into long 
curved comua. Cetacea (whales) have a highly rugous 
single vagina, a distinct, short uterine segment divided 
into two separate horns. The genitalia of Sirenia 
resemble those of the last group, but the cervix is better 
developed. In the last three orders the clitoris begins 
to be well developed and to present externally. Probos- 
cidea have a single vagina separated from the short 
uterine body by three transverse folds corresponding to 
the cervix; the two cornua are long and wide. 
''The foregoing orders present in their uteri all the 
essential characteristics of uterus bicomis unicollis with 
single vagina and are therefore the homologues of this 
anomaly in man." 
In the Peris sodactyla, the bicornate uterus has a 
body of a little less than half the whole length; there is 
a sphincter at the lower end of the body but no project- 
ing cervix. The cornua are longer still in the 
Artiodactyla and are coiled in a manner suggesting 
spiral sheep's horns; there is a differentiated projecting 
cervix. In cats the length of the uterine body and of the 
cornua are almost equal and both are flat tubes; the 
cervix is prominent and] the vagina long and rather 
smooth. The dog's uterus is similar but the two cornua 
are bound together or fused before the point at which 
their termini enter that of the uterine body; the cervix 
is not very prominent, but well formed and the vagina 
is rugous. These types coiTespond to the uterus cordi- 
formis. Lemurs have a common uterovaginal cavity 
like the Edentata. The lower monkeys possess a long 
