DEVELOPMENT OE THE SKULL IN STURGEONS. 
185 
List of Abbreviations. 
The Roman figures indicate nerves or their foramina. 
ad. rn. 
Adductor mandibuke. 
ms.pg. 
Mesopterygoid. 
al.s. 
Alisphenoidal region. 
mt.pg. 
Median metapterygoids. 
al.s. 
Alisphenoidal bony plate. 
mt.pg". 
Lateral metapterygoids. 
an. 
Anus. 
mx. 
Maxillary. 
aq.v. 
Aqueduct of vestibule. 
nc. 
Notochord. 
a.s.c. 
Anterior semicircular canal. 
ol. 
Olfactory capsule. 
au. 
Auditory capsule. 
Op. 
Opercular scute. 
bb. 
Barbel. 
o.s . 
Orbito-sphenoidal bony plate. 
b.br. 
Basi-branchial. 
p. 
Parietal scute. 
C 1 . 
Fore-brain. 
pa. 
Palatine bone. 
C 3 . 
Mid-brain. 
pa.s. 
Parasphenoid. 
c 3 . 
Hind-brain. 
p.br. 
Pharyngo-branchial. 
d. 
Dentary. 
P-f- 
Pectoral fin. 
e. 
Eye-ball. 
pg. 
Pterygoid bone. 
e.br. 
Epi-branchial. 
pg.q. 
Pterygo-quadrate. 
e.eth'. 
Ethmoidal bony plate. 
px. 
Pharynx. 
e.o. 
Ex-occipital region. 
p.op. 
Pre-opercular bone. 
e.pa. 
Et h m o - p alat ine. 
pr.o. 
Prootic bony plate. 
e.pa. 
Extra ethmo-palatine. 
p.s.c. 
Posterior semicircular canal. 
Frontal bony scute. 
pt.hm. 
Protractor hyomandibularis. 
f o. 
Fontanelle. 
pt.ob. 
Postorbital scute. 
9- 
Gills. 
q.c. 
Quadrate condyle. 
In. 
Heart. 
s.ob. 
Superorbital scute. 
h.br. 
Hypo-branchial. 
sp. 
Spiracle. 
h.hy. 
Hypo-hyal. 
sp.r. 
Spiracular ray. 
hm. 
Hyomandibular. 
sq'. 
Squamosal scute. 
hm.r. 
Hyomandibular ray. 
su.ob. 
Suborbital scute. 
h.s.c. 
Horizontal semicircular canal. 
sy. 
Symplectic. 
Ivy. 
Hyoid fold. 
t. 
Teeth. 
i.hy. 
Inter-hyal. 
t.cr. 
Tegmen cranii. 
i.tr. 
Intertrabecula. 
tr. 
Trabeculae. 
iv. 
Investing mass. 
u.l. 
Upper lip. 
1 
Liver. 
V. 
Vomerine bone. 
U. 
Lower lip. 
vb. 
Vestibule. 
m. 
Mouth. 
v.f. 
Ventral fin. 
mh. 
Meckel's cartilage. 
y.xt. 
Yolk-mass and stomach. 
ran. 
Mandibular fold or bar. 
2 B 
MDCCCLXXXIL 
