. 2. The outer genital aperture of the same young female displayed as an anatomical
preparation, and held open by a style to show specially cl., the
clitoris. Drawn of natural dimensions.
3. An abdominal view of the unimpregnated uterus of Tlatanista reduced to
3rd natural size: r., portion of rectum; u., uterus; o., ovary; fm., fimbriated
extremity, pavilion and orifice of the fallopian tube; b., urinary
bladder; po., pouch or peritoneal diverticulum alongside the neck of the
bladder. Reduced.
4. Sketch of the foetus of Tlatanista gangetica from a photograph £ natural
size. Dorsal view and reduced to scale |rd of the natural size of the
animal: b., blow-hole; d. f , dorsal fin; <?., coil of the umbilical cord.
PLATE XXXIII.
1. The genitalia and foetus in utero of Orcella brevirostris, reduced -|rd natural
size: r. h., the empty right horn of the uterus, the left is opened, exposing
the young animal in situ and bent upon itself; am., amniotic sac; c.,
umbilical cord; t., tail twisted in a comer of the folds of the cavity;
b., position of blow-hole; h., hairs or bristles of snout; m. g., mammary
gland uncovered; m., the external mammary slit, the nipple being hidden
in the slit; v., vulval cleft; pe., perinaeum; a., anus; /., fallopian tube;
fm., its fimbriated extremity.
2. A sketch of the os uteri mternum of gravid of O. brevirostris, J natural size.
3. The inner uterine surface and opening of the fallopian tube ( f . ) of the
same cetacean, and about natural size.
PLATE XXXIV.
1. A deep view of the pregnant uterus and neighbouring parts of JPlatanista
(see text) seen with part of the left cavity wall removed, the whole
reduced to ^th of its original magnitude: le., interior of left hom; pa.,
passage leading to rh., the right uterine hom; o., ovary of left side;
r., rectum cut short.
2. Ecetal envelopes of Tlatanista gangetica, reduced to fth their natural size.
The smaller right horn is turned forwards to show the uterine pouch, the
larger gravid left hom has its chorionic membrane slit open: ch., chorion
; am., amnion; t., termination of the amniotic sac on the right side;
al., allantoid, showing dots or specks which represent the amniotic
corpuscles; f o., pole corresponding to left fallopian orifice; c., umbilical
cord; b. s., position of one of the bare spots of right chorion, viz., that
corresponding to the mouth of the fallopian tube; sp., sac which depends
into common cavity of uterus.
( 13 )
Eig. 3. Drawing (natural size) of the bare patch on sac (sp., fig. 21) depending into
the common cavity of the uterus, and placed opposite to the os uteri
i/nternum of Tlatanista.
,, 4. A portion of the chorion of Orcella brevirostris with a bare surface occupied
by a pedunculated body (p . ), of natural size.
„ 5. The glandular body, of natural size, obtained from the allantois of Tlatanista.
See description of same in text.
„ 6. A portion of the umbilical cord of the Gangetic Dolphin Tlatamsta, of
natural size, and showing the remarkable moniliform character of the
vessels. A slice of the wall has been taken away, and three or four
enlargements or chambers are seen communicating by narrow orifices,
through which pointers have been introduced.
„ 7. A drawing magnified 2 diameters of a similar vascular dilatation to the
foregoing in one of the central vessels of the cord of Tlatamsta.
„ 8. Much enlarged view of two yellow bodies, or supposed lymphatic sacs, I. s.,
of the cord of Orcella, occurring in the loose areas between the vessels, v.
„ 9. A drawing illustrative of the sac and .other bodies on the umbilical cord of
Orcella brevirostris. The part represented is at the bifurcation of the
vessels to the right and left cornua, and is about natural size: gl., hollow
glandular structure, with which at the upper end there communicates
(pi.) a beaded or moniliform tube and inferiorly another vessel leading
to (I. h.), an opened lymphatic heart?; I. h.,2 a second smaller lymphatic
heart ?; pp. represent two of the pedunculated bodies described in the
text.
„ 10. A representation, of natural size, of the manner in which the vessels of the
umbilical cord of Orcella intercommunicate obliquely the one with the
other.
PLATE XXXV.
Eig. 1. A drawing from nature, but reduced to ^rd of its original dimensions, of the
bare patch in the left hom of the chorion of Tlatanista running along
the course of the umbilical vessels: d., dorsal or anterior margin; v.,
ventral or posterior margin; r., right pole; I., left pole; c., crypt where
the vessels break off; p., small pedunculated body.
„ 2. The surface of the chorion of Orcella brevirostris exhibiting patches of
bare.spots : v„ blood-vessels traversing the membrane; natural size.
„ 3. Apiece of the chorion of Orcella brevirostris enlarged 4 times natural size
to display a single bare spot and villous character of membrane around:
the bare surface was opposed to a bare surface of the uterus.
„ 4. A piece of the uterus of Orcella brevirostris, showing the bare patches on
its mucous surface. Natural size.
„ 5. A small portion of the same enlarged 4 times, and demonstrating a bare
spot occupied in its centre (u.), with orifice of the utricular gland.