(c) The sternum, consisting of a median row of cartilages which are believed
to be derived from the shoulder girdle. It does not, therefore, corre-
spond to, or is not homologous with, the sternum of the Pigeon or the
Rabbit, which is derived from the ribs. The sternum consists of the
following parts :—


(i) The omosternum, consisting of two parts—viz. an anterior
cartilaginous part (sometimes called the episternum) and a
posterior bony rod (the omosternum proper).
(ii) The two cartilaginous epicoracoids.
(iii) The metasternum, consisting of two parts—viz. an anterior
bony part (sometimes called the mesosternum or sternum)
and a posterior cartilaginous part (sometimes called the
xiphisternum).
[In the Platana the sternum consists of the following parts :—

(i) The two cartilaginous epicoracoids.
(ii) The metasternum, which is broad and consists of cartilage only.]

Make a sketch of the pectoral girdle. (See Fig. 76, A or B, page 218.)

2. Cut through the coracoids and clavicles on each side, close to the base of


the arm, and carefully remove this part of the pectoral girdle and sternum so as
to expose the heart lying beneath.
Alimentary System.
Make a sketch showing the heart, lungs, liver, gall-bladder, bile-duct
(common duct of liver and pancreas) going to the duodenum, exposed parts of
the stomach, duodenum, small intestine (or ileum), large intestine (or rectum),
pancreas, spleen, and urinary or cloacal bladder.
