218 EDWARD L. RICE 
EXPLANATION OF FIGURES 
Figures 1 to 8 were drawn by Miss Mabel Hedge from wax-plate models. The 
length of the model represented in figures 1, 2, and 3 was exaggerated about 10 
per cent in the modeling, so that the skull appears abnormally long and narrow, 
in the other models the exaggeration is so slight as to be negligible. 
Figures 9 to 33 are by the author; all except the last two were drawn with the 
camera lucida or projection apparatus. 
The magnifications of figures from models are expressed in relation to the 
actual specimens, thus corresponding with those of figures of sections. 
Dimen- 
sions and relative ages of the different ‘stages’ are recorded in the text, page 122 
The relative positions of sections figured are indicated by parenthetical num- 
bers—the numbers of the sections in their respective series. 
Each series 1s num- 
bered from anterior to posterior; that for stage 5 contains 358 sections, that for 
stage 6 contains 464 sections. 
All sections are 15 pw in thickness. 
The following abbreviations are employed: 
ABBREVIATIONS 
ad.co., aditus conchae 
b.pl., basal plate 
b.pl’., extension of basal plate lateral 
to otic capsule 
br 1, first branchia! arch 
br.2, second branchial arch 
br.2’, isolated fragment of second (?) 
branchial arch 
c.art., cartilago articularis of pterygoid 
c.ect., cartilago ectochoanalis 
c.hyp., cartilago hypochiasmatica 
c.meck., Meckel’s cartilage 
c.par., cartilago paraseptalis 
c.sph-e., cartilago sphenoethmoidalis 
can.s-c.a., anterior semicircular canal 
can.s-c.l., lateral semicircular canal 
can.s-c.p., posterior semicircular canal 
caps.jac., capsule of Jacobson’s organ 
cav.coch., cavum cochleare 
cav.vest.a., cavum vestibulare anterius 
cav.vest.p., cavum vestibulare pos- 
terius 
ch., notochord 
co., concha 
co.jac., concha of Jacobson’s organ 
col., columella auris 
com.p-f., postfacial basicapsular com- 
missure 
com.pr-f., prefacial basicapsular com- 
missure 
con., occipital condyle 
cr.par., erista parotica 
cr.sel., erista sellaris 
d.l.na., duct of lateral nasal gland 
d.na-lac., nasolacrymal duct 
epipt., epipterygoid 
f.ap., foramen apicale 
f.end., foramen endolymphaticum 
f.ep., foramen epiphaniale 
f.jug., foramen jugulare 
f.mag., foramen magnum 
f.n.VI, foramen for nerve VI 
f.n.VII, foramen for nerve VIT 
f.n.VIIT.a., foramen for anterior ramus 
of nerve VIII 
fn. Villps, foramen “for 
ramus of nerve VIII 
f.n.XII.a., anterior foramen for nerve 
XII 
f.n.XII.p., posterior foramen for nerve 
sa 
fen.b-c.p., fenestra basicranialis pos- 
terior 
fen.coch., fenestra cochleae 
fen.e-op., fenestra epioptica 
fen.hyp., fenestra hypophyseos 
posterior 
