cartilage.
ar., angulo-splenial -(On Frog Section 34, for Articulare read
-Angulo-Splenial_)-.
-b., parachordal part of brain box-.
b.c., brain case.
b.h., body of hyoid.
b.r., branchial arches.
CH = a.c.
c.t., cornua trabeculi.
d., dentary.
e., eye.
E.N., external nares.
e.o., exoccipital bone.
f., fenestra (membranous part of cranial wall).
-f.p., fronto-parietal.-
h.m., hyomandibular cleft = Eustachian tube and ear drum.
mb., mandible.
[M.C., Meckel's Cartilage.]
m.mk., mento-Meckelian bone.
m.p., mouth passage.
mx., maxilla.
n.c., notochord.
n.o., nasal organ.
n.p., nasal passage.
ot., or o.c., otic (auditory) capsule.
pal., palatine bone.
PAL., hard palate of Mammal.
p.c., parachordal.
p.f., [parieto-frontal] -see f.p.-
p.m., premaxilla.
P.N., internal nares.
p.o., prootic bone.
p.p., palato-pterygoid cartilage.
psph., parasphenoid bone.
pt., pterygoid bone.
q., quadrate cartilage.
q.j., quadrato-jugal.
s.e., sphenethmoid bone.
sq., squamosal.
t., trabecular part of brain box.
t.c., trabecula.
th.h., thyrohyal.

{Illustration: Diagram Sheet 14.}

Sheet 15

Figure 1. Dissection of -Male- [Female] Dog-Fish to show alimentary
canal, the pericardium also being opened and the cloaca slit up.
[Above is also seen the dorsal view of the head.]

Figure 2. The pelvic girdle and fin skeleton [of a male].

{No Figure 3, in First Edition.}

Figure 4. The spiral valve in the colon. {Figure 3, in Second Edition.}

a.p., abdominal pore.
aur., -auricle- [atrium] of heart.
b.d., bile duct.
b.pt., basi-pterygium.
-cl., clasper.-
cl.c., -its- [the] supporting cartilage [of the clasper].
co., colon.
d'dnm., duodenum.
e., the eye.
g.bl., gall bladder.
g.s., gill slits.
L.Lv., left lobe of liver.
M.Lv., middle lobe of liver.
olf., olfactory opening.
[pan., pancreas.]
pcd., pericardial wall.
pel.g., the pelvic girdle.
p.p., arrow through pericardio-peritoneal canal.
r.g., rectal gland.
[R.Liv., right lobe.]
sp., spiracle.
spl., spleen.
st., the stomach.
s.v., sinus venosus.
u.g.p., uro-genital pore.
v., ventricle.

{Illustration: Diagram Sheet 15.}

Sheet 16.
Figure 1. Circulation of the Dog-Fish.

Figure 2. Simplified and more typical fish circulation, in which the
posterior cardinals have not coalesced in the median line. The
Cuvierian veins = the vena cava superior of the higher type; the
posterior cardinal is represented by the azygos vein in the Rabbit.
Compare Sheet