PLATE 4 
EXPLANATION OF FIGURES 
All figures of Heterodontus francisci. 
8 
Antero-lateral view of left side of pectoral girdle (one-half natural size). 
9 Lateral view of extrahyoid cartilage (x 4). 
10 Antero-lateral view of first branchial arch; (one-half natural size). 
11 Ventral view of median basibranchial cartilages (natural size). 
12 Posterior view of the spiracular cartilage (X 1). 
13 Dorsal view of right half of pelvic girdle (natural size). 
14 Antero-lateral view of the fourth and fifth branchial arches, with attached 
rudimentary sixth arch (one-half natural size). 
articular process pelvic fin 
anterior projection of pectoral 
a.pl., 
GT, 
arch 
a.pt., articular process pectoral fin 
b.b., basibranchial 
b.h., basihyal cartilage 
r., branchial ray 
c-b. 1-5, first to fifth ceratobranchials 
co., coracoid cartilage 
e-b. 1-5, first to fifth epibranchials 
exib., 
f.pl., 
f-pt., 
extrabranchial 
foramen through pelvic girdle 
foramen through pectoral girdle 
g.p., glossal process 
h-b. 1-4, first to fourth hypobran- 
chial 
m.p., posterior median piece 
p-b. 1-5, first to fifth pharyngobranch- 
ials 
sc., scapula 
