180 EDWARD L. RICE 
parietalis media (dorsal), the pila prootica and corresponding 
upward projection of the basal plate (posterior), and the tra- 
becula (ventral). Through this opening the oculomotor (n. I/T.) 
and trochlearis (n.JV.) nerves leave the cranial cavity, as de- 
scribed in Lacerta; also the abducens (n.VJ.), discussed in an 
earlier paragraph (p. 134). 
Fenestra prootica inferior (fen.pr-ot..), bounded by the pila 
prootica (anterior), the taenia parietalis media and taenia mar- 
ginalis (dorsal), the otic capsule (posterior), and the basal plate 
(ventral). The dorsoposterior portion of this very irregular 
fenestra contains no important organs, but through the lower 
portion, incisura prootica, the trigeminus nerve emerges by two 
main trunks (n.V.1. and n.V.2-3.), each swelling into a large 
ganglion mass. The two ganglia (fig. 19, g.V.a. and g.V.p.), 
rather well separated from one another as in Lacerta, but not 
in Emys (Kunkel, ’12 b), largely fill the pocket formed between 
the pila prootica, otic capsule, edge of basal plate, and epiptery- 
goid. The three main branches of the nerve are distributed as 
in Lacerta, the first (fig. 21, n.V.1.) arising from the anterior 
ganglion and passing forward, above the processus basiptery- 
goideus and between the pila prootica and epipterygoid, while 
the second and third (figs. 19 and 21, n.V.2. and n.V.3.) leave 
the posterior ganglion in a more lateral direction and are sepa- 
rated from the first by the cartilaginous rod of the epipterygoid. 
In stage 5 only the fenestra optica (fig. 3, fen.op.) is fully 
retained. Posterior to this the lateral wall has become so rudi- 
mentary that the fenestra epioptica, fenestra metoptica, and 
fenestrae prooticae, superior and inferior, have become con- 
fluent as a single enormous fenestra (fig. 3 fen.y.), whose sub- 
division is barely suggested by the cartilage remnants already 
described. 
The variation in the reptilian series as regards the degree of com- 
pleteness of the lateral temporal wall necessarily leads to corre- 
sponding differences in the fenestrae. Most interesting is the occa- 
sional division of the fenestra metoptica in such a way that the 
oculomotor and trochlearis nerves are provided with independ- 
ent foramina. This has been recorded for Chelone by Gaupp 
