16 The Cephalic Veins and Sinuses of Reptiles 
have little to add to Grosser and Brezina’s description of this vein, whose 
history, as given by these authors, 95, is closely correlated with that of 
the vena cerebralis anterior. In earlier embryonic stages the latter is a 
continuous vein which extends from the vena longitudinalis cerebri to 
the anterior part of the vena jugularis interna (compare Text Fig. 1). 
In later stages the vena cerebralis anterior breaks in the middle, the 
dorsal portion discharging into the median vein, while the ventral part 
retains its relation to the vena jugularis interna. At this time the 
secondary connection (secundire Verbindung) is formed, between the 
ventral part of the vena cerebralis anterior and the vena cerebralis media 
secunda. In later stages the ventral part of the vena cerebralis anterior 
is drowned by the posterior extension of the sinus orbitals. Hence, in- 
the adult lizard the secondary connection acquires a direct outlet into 
the sinus orbitalis (s. V., Text Fig. 2; Fig. 5, Plate I). 
The dorsal part of the vena cerebralis anterior has not been identified 
in the adult lizard. It evidently undergoes further reduction before the 
adult condition is reached. 
b. VENA PTERYGOIDEA AND THE SINUS PALATINUS. 
1. VENA PTERYGOIDEA (v. pt., Text Fig. 2).—This vein begins at the 
posterior border of the foramen suborbitalis, where it receives the drain- 
age of the posterior part of the sinus palatinus lateralis. The vein runs 
caudad on the dorsal side of the pterygoid bone (v. pt., Fig. 4, Plate I) 
until it reaches the foot of the columella (os epipterygoideum), on whose 
median side the vein bends dorsad and enters the vena jugularis interna. 
The yena pterygoidea receives small tributaries from the pterygoid 
bone and from the oral mucous membrane; its most important tributary, 
however, is the sinus palatinus. 
2. SINUS PALATINUS (Text Fig. 2; Figs. 2 and 3, Plate I1).—This 
sinus lies in the submucosa of the roof of the mouth. It begins near 
the rostrum and extends caudad, on each side of the head, as far as the 
pterygo-transverse bar which forms the posterior boundary of the fora- 
men suborbitalis. The sinus includes a sinus palatinus medius, the 
paired sinus palatinus lateralis, and two sinus palatini transversi. 
The most anterior part of the system is the sinus palatinus trans- 
versus anterior (s. p. t. a., Text Fig. 2), which hes behind the dentary 
portion of the intermaxillary bones, through which it communicates with 
the vena rostralis, as elsewhere described. The sinus palatinus trans- 
versus anterior gives rise on each side to a sinus palatinus lateralis (s. p. 
l., Text Fig. 2; Figs. 2 and 3, Plate IL), which forms, directly behind its 
