nternal jugular vein.
i.il.a., internal iliac artery.
i.il.v., internal iliac vein.
k., kidney.
lv., liver.
l.g.v., lienogastric vein (portal).
m.v., mesenteric (portal system).
p.m.a., posterior mesenteric artery.
p.v., main portal vein.
p.a. pulmonary artery.
r., rectum.
r.a., renal artery.
r.v., renal vein.
s.v., and a., spermatic (or ovarian) vein and artery (to genital
organ).
s.mes.a., superior mesenteric artery.
s.-cl.a., subclavian artery.
s.-cl.v., subclavian vein.
v.c.s., vena cava superior.
v.c.i., vena cava inferior.
v. or vn., ventricle.

Figure 2. Figure of Circulation (simplified) illustrating certain points in
development to be referred to later.

Figure 3. Respiration. See text, Section 41.

Figure 4. Blood. See text, Section 35.

{Illustration: Diagram Sheet 2.}

Sheet 3

Histological Figures, 1.

{No numbers I., or II.}

Figure III. An amoeba.--
n., nucleus.
ns., necleolus.
c.v., contractile vacuole.

Figure IV. Embryonic tissue from the blastoderm of a chick.

Figure V. Columnar epithelium.--
g.c.1, g.c.2, g.c.3, successive phases in the development of a goblet
cell.

Figure VI.
g.end., is geminating endothelium; the cells divide and apparently
drop off to become white corpuscles in the lymph current.
sq.end., squamous endothelium from the mesentery.
sq.ep., squamous epithelium (from the mucous membrane within the
cheek).
st., are opening (stomata) communicating between the lymphatics in
the mesentery and the peritoneal (coelomic) space.

Figure VII. Ciliated epithelium from the roof of the frog's mouth.

Figure VIII. Forms of glands.--
g.ep., is a gastric gland from the stomach; trs., below, is cross
section. This is one of the simplest types of gland.
s.g., a sweat gland, is also a simple tube, but convoluted below.
r.g., is a racemose gland, such as the pancreas, Brunner's or the
salivary glands.

The kidney, we shall see later, is simply an aggregate of branching
tubuli (Sheet 7).

Figure IX. A duodenal villus.--
lac., the lacteal.
v., the vein.

Figure X.a. Diagram of liver structure.--
b.d., the inter-lobular bile duct.
h.a., the hepatic artery, bringing blood to oxygenate and nourish the
liver tissue, and similarly distributed.
h.v., the hepatic vein taking blood from the liver to the heart, its twigs
commencing in the lobuli (intra-lobular).
lb. lb., lobuli.
p.v., the portal vein bringing blood, from which substances are to
be elaborated, into