-Amphioxus_

Two specimens of this type should be obtained. It should be examined entire by the naked eye and with the low power of the microscope. Immersion, in glycerine will render it more transparent; or it may be cleared with oil of cloves, put up temporarily in that, or permanently in Canada balsam. One specimen should then be pinned out in the dissecting dish, ventral side uppermost, and the atrium opened to expose liver and pharynx. A part of the pharynx may be examined with the low power to see the form of the gill slits. The second specimen should be soaked in turpentine for some time, and then dropped into melted paraffin wax. Transverse sections may then be cut with a razor, the paraffin wax removed from these by solution in turpentine, the turpentine in its turn dissolved out by alcohol, and the sections, after immersion in oil of cloves, may be transferred to Canada balsam for examination and preservation. This work should not be attempted until some practical histological work has been done in botany, and it may be altogether avoided by the purchase of stained and mounted sections.

-Development_

Laboratory work in this portion of the science is not usually undertaken by elementary students of biology, but the reader will probably find it helpful, in the realization of the facts given in this book, to look out for frog spawn, in February and March, and to catch and examine tadpoles of various sizes. A small dissecting dish may be made by pouring melted paraffin wax into one of those shallow china pots chemists use for cold-cream, and tadpoles may be pinned out with entomologists' pins and dissected with needles. But this is a work of supererogation. Partially incubated hen's eggs may be obtained at a small cost almost anywhere, and the later stages profitably examined and dissected under warm water. For a clear understanding of the allantois and amnion, this last is almost indispensable. A few microscopic slides of sections of embryonic chicks should also be compared with our rough diagrams.

-{Key for Dissection Sheets, and Abbreviations.}_

Sheet 1

Figure 1. Main facts of the Rabbit's Anatomy (diagrammatic).
an., anus.
a.ao., arch of the aorta.
au., auricle.
a.r., ad-renal body.
br., brain.
b.d., bile duct.
brch., bronchus.
cd.st., cardiac end of stomach.
co., colon.
cae., caecum.
ddnm., duodenum.
d.ao., dorsal aorta.
dia., diaphragm.
ep., epiglottis.
g.d., genital duct (either sex).
il., ileum.
in.art., innominate artery.
k., kidney.
lg., lung.
lv., liver.
l., larynx.
l.s.c., [l.c.c.] left common carotid artery.
m., mouth.
na., nasal passage.
oes., oesophagus.
p.v., pyloric valve.
p.d., pancreatic duct.
pt., peritoneal cavity.
r., rectum.
st., stomach.
[stm., sternum.]
s.r., sacculus rotundus.
s.c., spinal cord.
tr., trachea.
ur., ureter.
ur.b., urinary bladder.
v.b., a vertebral body.
v.ap., vermiform appendix.
v.v., [v.p.] velum palatium.
v., ventricle of heart.
v.c.i., vena cava inferior.
Figure 2. The Liver (diagrammatic).
g.b., the gall bladder.
r.l., r.c., l.l.., l.c., right lateral and central, and left lateral and
central, lobes respectively.
sp., the Spigelian lobe (fits into angle of stomach and oesophagus).