(_a_) The ovaries, a pair of irregularly-lobed organs usually
consisting of a mass of rounded black and white bodies, the ova. The
ovaries are attached to the dorsal wall of the body cavity by a fold
of the peritoneum.
(_b_) The corpora adiposa lying in front of the kidneys.
(_c_) The long convoluted oviducts opening into the body cavity in
front and into the cloaca behind.
The ureters open separately into the cloaca in the female.
Make a drawing of the urinogenital system.
[Illustration: FIG. 10.--Female Urinogenital System of Xenopus and
Rana.]
_Fifth Day._
=Skeletal System= (_continued_).
A. The Pectoral and Pelvic Girdles and Limbs.
1. Detach a fore-limb with the remaining parts of the pectoral
girdle. Make a preparation showing these various parts:--
Supra-scapula, scapula, remainders of the clavicle and the coracoid,
humerus, radio-ulna, carpal bones, and digits. Draw these parts.
[Illustration: FIG. 11.--Pectoral Girdle of Xenopus and Rana.]
2. Detach the pelvic girdle from the transverse processes of the 9th
vertebra. Remove it with the hind-limbs from the body. Detach the
femur from one side of the pelvic girdle, and make a sketch showing
the following parts of the pelvic girdle:--Acetabulum, ilium,
ischium, and pubis.
[Illustration: FIG. 12.--Pelvic Girdle of Xenopus and Rana.]
Make a preparation and a sketch showing the femur, tibia-fibula,
astragalus, calcaneum and the other bones of the tarsal region, five
metatarsals, and digits. Number the digits from the inner side.
[Illustration: FIG. 13.--Hind and Fore Limbs of Xenopus.]
B. The Vertebral Column.
1. Remove the skin and muscles from the dorsal surface of the back to
show the nine vertebræ and the urostyle. Make a drawing showing the
vertebræ with their transverse processes, and the urostyle attached
to the posterior end of the 9th vertebra.
[Illustration: FIG. 14.--Vertebral Column of Xenopus and Rana.]
The 2nd, 3rd and 4th vertebræ bear long transverse processes curved
backwards, those of the 3rd and 4th being tipped with small
cartilaginous ribs. The transverse processes of the 5th, 6th, 7th and
8th vertebræ are slender and project forwards and outwards. The 9th
vertebra has long flat wing-like processes attached to which are the
ilia of the pelvic girdle. The urostyle is fused to the 9th vertebra.
[_In the Frog the transverse processes are produced outwards and they
do not bear cartilaginous ribs. The urostyle is attached to the 9th
vertebra by two facets._]
Note the intervertebral foramina for the exit of the nerves from the
spinal cord, and the intervertebral discs.
2. Remove, examine, and draw the 1st or atlas vertebra, note its
ring-like form, absence of transverse processes, the concave facets
by which it articulates with the two occipital condyles of the skull.
3. Remove, examine, and draw the 3rd vertebra and note the
opisthocœlous centrum, neural arch and neural spine, anterior and
posterior zygapophyses, the transverse processes, and the
cartilaginous ribs.
[_The centrum is procœlous in the Frog and there are no ribs._]
4. Remove and examine the 8th vertebra and note that the centrum is
opisthocœlous. Make a drawing of a section showing the centrum.
[_In the Frog the centrum is amphicœlous._]
5. Remove and examine the 9th vertebra or sacrum, and note that the
centrum is slightly convex on the anterior surface. The urostyle is
fused to the posterior surface of the 9th vertebra. Note also the
long flat wing-like transverse processes.
[_In the Frog the centrum is also convex anteriorly and on the
posterior surface there are two convex facets for the articulation of
the urostyle._]
_Sixth Day._
=Skeletal System= (_continued_).