spiracle, scales passing over lips, and cloaca.
Cut off tail below the cloacal opening. The males are distinguished by
the large claspers along the inner edge of the pelvic fin. Open up body
cavity. Usually this is in a terrible mess in the fish supplied by
dealers, through the post-mortem digestion of the stomach. Wash out
all this under a stream of water from a tap or water-bottle. Frequently
the testes are washed out of the male in this operation and ova from
the loose ovaries in the female. Now compare with figure given in this
book, allowing for the collapse of the stomach, if it has occurred. Cut
through the oesophagus and rectum, and remove alimentary canal
from body; cut open and wash out the intestine, and examine spiral
valve. Now make a careful examination of the cloaca and its
apertures, and dissect away the peritoneum hiding the kidney. In the
female find the opening of the oviducts in front of the liver. Remove
liver, and cut off body now behind pectoral fin. Before throwing tail and
hinder part of body away, note the myotomes of body wall, the
notochord and vertebral body, neural canal, and, in the tail, the
haemal canal. [(See {Section 9 the Dog-fish})]

{Lines from First Edition only.}
-The relation of the vertebral bodies to the notochord may be very
well seen by taking successive slices, about one-tenth of an inch
thick, through the vertebral body. The cartilage is hard and
semi-transparent, the notochord jelly-like, least at the centres
of the centra, and at a maximum intervertebrally.-

[The notochord is a soft jelly.] Cut away the ventral part of the pectoral
girdle, to open pericardium. With a seeker, make out the pericardio
peritoneal opening. Cut into the sinus venous, and run seekers into
the Cuvierian and hepatic sinuses. [Cut open the Cuvierian and
posterior cardinal sinuses, and run seekers into their affluents.]
Dissect along the truncus arteriosus to afferent branchials. [Cut away
the heart and oesophagus; run a seeker up the dorsal aorta and cut
along it from the ventral side to subclavian and efferent branchial
arteries.] Skin the top of the head. Note, while doing this, the yellow,
jelly-like sense-tubuli beneath the skin. Shave off top of brain-case,
and leave the head in spirit for a week or so.

Second Dissection.-- Place the head with the ventral side downward,
skin all the dorsal surface as yet unskinned. Refer to book for
precise position of the anterior cardi