6 The Cephalic Veins and Sinuses of Reptiles 
I. THE CEPHALIC VEINS AND SINUSES OF LACERTA 
AGILIS. 
Vogt and Jung, 89-94, have recognized three chief veins in the head 
of Lacerta ocellata, a “‘ supraorbital,” an “ infraorbital,” and a “ jugular,” 
but the description of these veins is very meager. More or less incom- 
plete observations on isolated vessels have also been made by different 
authors, whose descriptions, based on different species, are referred to 
later. The cephalic veins of Lacerta agilis have been studied by Grosser 
and Brezina, 95, who have described in an excellent paper, the develop- 
ment of the larger veins, including both the primitive arrangement out- 
lined above and the changes which occur in later embryonic stages. 
The following description of adult conditions is based chiefly on 
Lacerta agilis, but it will apply also with httle modification to the Ameri- 
can lizard, Cnemidophorus sexlineatus, which is occasionally referred to 
by way of comparison. Other forms are also utilized in connection with 
the study of special parts. 
The head of Lacerta includes two almost distinct venous territories: 
(1) A dorsal one which includes the face and cranium and is drained 
by the vena jugularis interna; (2) a ventral territory which includes 
the tongue, larynx, pharynx, trachea, and the floor of the mouth. It is 
drained by the vena trachealis. . 
A. THE TERRITORY OF THE VENA JUGULARIS INTERNA. 
The cervical part of the vena jugularis interna of lizards is briefly 
described by Corti, 41, Parker, 84, and Vogt and Jung, 89-94. ‘The 
cephalic portion of the vein is probably included in the vena infra- 
orbitalis of Vogt and Jung, 89-94, p. 714, although its relations are 
inaccurately shown in their Fig. 290, p. 712. The anterior part of the 
vein has been well worked out by Grosser and Brezina, 95. 
The authors last mentioned have shown that in the earlier embryonic 
stages of the lizard the vena jugularis interna (vena cardinalis) hes on 
the ventral side of all cranial nerve trunks. In later stages the anterior 
part of the vein retains this primitive relation, while the post-trigeminal 
portion shifts its position to the dorsal (lateral) side of the posterior 
nerves, the change being effected by ring formation around the roots of 
the nerves, and subsequent obliteration of the ventral part of the rings. 
Grosser and Brezina retain for the subneural vessel the name vena 
cardinalis, while the posterior part of the vein is called vena capitis 
lateralis. In the following account I shall use the name vena jugularis 
