142 EDWARD L. RICE 
in an almost horizontal position along the dorsal margin, while 
the lateral ‘horizontal’ canal is nearly vertical. In the turtles 
Nick and Kunkel report the exterior modeling as much less deli- 
cate than in the lizards. 
3. Interior of auditory capsule 
In the study of the interior of the ear capsule I make free use 
of an unpublished thesis by Mr. Joseph I. Taggart. The inter- 
pretation of the space relations of a cavity is notoriously difficult, 
even when the cavity is far less complicated than that of the ear. 
With this difficulty in view, Taggart made a solid model or cast 
of the cavity of the otic capsule of stage 5 of Eumeces, reproduced 
in figure 5 of this paper. The membranous labyrinth was also 
modeled for comparison. As there are no striking departures 
from Lacerta, a brief summary will suffice in connection with the 
figure. 
The principal division of the cavity is the cavum vestibulare 
posterius (cav.vest.p.), with its three extensions—anteroventral, 
the cavum cochleare (cav.coch.); posteroventral, the recessus 
ampullaris posterior (r.amp.p.); posterodorsal, the recessus pro 
sinu superiore utriculi, located below the junction of the anterior 
and posterior semicircular canals (can.s-c.a. and can.s-c.p.), but 
invisible in the figure because of its position median to the cavum 
vestibulare posterius. To the anterior the cavum vestibulare 
posterius is connected, but less intimately, with the cavum vestib- 
ulare anterius (cav.vest.a.). The courses of the three semicircular 
canals are easily followed in the figure. 
In the lateral part of the cavum vestibulare posterius is located 
the sacculus, with which are connected the cochlea and the ductus 
endolymphaticus. The cochlea extends downward and forward 
into the cavum cochleare, while the ductus endolymphaticus 
passes to the median wall of the cavum and through the foramen 
endolymphaticum into the brain cavity, where it expands into 
the capacious endolymph sac. Median to the sacculus in the 
cavum vestibulare posterius is a part of the utriculus, enlarged 
