oids on either side, and remove ventral part of shoulder
girdle, to expose the heart. Open out the cut portions of body wall and
pin. The veins going towards the heart should now, with a little
examination, be evident. Make out the external jugular, the
innominate, and its two branches, and the pulmo-cutaneous and vena
cava superior. Clear by carefully picking away any shreds of
semi-transparent tissue. Make out, by feeling, the position of the
hyoid body, and of its anterior cornua. Note the hypoglossal nerve
(first spinal) running ventral to this, and the ninth cranial nerve,
running parallel to it but dorsal to the hyoid-- hidden therefore by
the hyoid, and reappearing in front. The vagus may also be made out less
distinctly, running "postero-ventrally" towards the heart. By clearing
the muscle by the rumus of the jaw, VII. may be seen, and the third
branch of V., running across the jaw at about the middle of its length.
Pick off the thin transparent pericardium from the heart very carefully,
and proceed to cut away all the veins made out. The truncus
arteriosus may then be followed up as it branches. Note all the
branches shown in the figures in this book. The precise position of the
vessels will vary to a certain extent with the attitude in which the frog
is pinned. The cutaneous artery will prevent the student following up
the aortic arch until it is cut; then the arch may be followed round until
it meets its fellow to form the dorsal aorta. Note the sympathetic
again. Make careful drawings of all this. Cut off lower jaw, and note
posterior nares and Eustachian openings. If time allows, remove the
heart, and examine by cutting open and washing. (Compare, Section
44) Remove eyeball, to see the first and second branches of the fifth
nerve, and the Vidian (i.e. palatial) branch of the seventh.

Third Dissection.-- Read the account of the frog's skull carefully.
Take the head of a recently killed frog and drop into boiling water for
a minute. Then pick off, very carefully, muscle, connective tissue,
nerves, and etc., to clear the cranio-facial apparatus; examine the
bones, compare with figures given in this book, and draw. Take the
head, which has been in spirit a fortnight or so, pick away cranium,
and compare brain with figures given. Examine ventricles, by taking
sections, after drawings have been made.

-The Dog-Fish-

First Dissection.-- Examine external characters, nasal grooves-- no
internal nares-- fins,