398 SURG. J. C THOMPSON ON THE 
they are increased or suppressed, and the gastrostege level at 
which these changes occur may be thus presented :— 
17 vows, [X row added, right 15th, left 17th gastrostege, making : 
OT EX eters amide, al Oth _ leaving : 
ip oy a. LN ee » 105th, ,, 104th 
15 ,, which are continued to the vent. 
9? 2) 
PSAMMOPHIS SIBILANS Linneeus. 
Spectmen.— Brit. Mus. Nat. Hist. Ex. No. ’13-1. Nile Delta, 
Egypt. Adult male: total length 969, tail 315 mm. 
The tracheal membrane is narrow, being only 1:5 mm. wide at 
the base of the heart; it is confined to the left side of the tube 
and the air-cells commence at the level of the auricles of the 
heart. The bronchus is continued as a fine intrapulmonary 
fibrous band to the level of the 55th g. The right lung is lined 
with pulmonary tissue to the 58th g. and is without a free apex. 
The left dung, 3 mm. long, opens into the trachea one gastrostege 
below the apex of the heart. 
The vertebral artery arises from the right aortic arch at the 
36th g.; it gives off six intercostal branches which enter in 
the median line:—I.-33; 11.-32; IJI.-29; IV.-28; V.—25; 
VI.-23; a branch to the esophagus at 20 g.; at the 18th g. it 
bifurcates, sending a small intercostal branch into the parieties, 
and a larger one onto the dorsal surface of the cesophagus. 
The right aorta gives off an intercostal at the 36th g. The 
common aorta begins at the 43rd g.; the first few intercostal 
branches enter on the left side. 
The external landmarks of the principal viscera in terms of 
gastrosteges are as follows :— 
CRISUKOSIEGIVES \ooecadnescsen’ 2k 3 166 100 per cent. 
Me ebNPO Xe aa naaes sce eeee eae A] 24:7 
Mai RENes AUN se. Sesser eae os 48 28°9 
Sy Sia eB ee aaa AON ea 82 49-4 
Gallebladder o.2 j42e erode se 100 60°3 
KGolmeyampiohit. hips. oes rece 142 85:7 
is ae ae TCU 2 hae eae 163 98 
go iptledibs: GW eeccetetieee ciuehes ie 146 88 
5 Rae RETA LY eocters Wan aes 164 98°8 
There are 19 scale-rows on the neck. On the body there are 
17 anteriorly, decreasing to 15 and finally to 13 rows posteriorly. 
OPHIOPHAGUS BUNGARUS Schlegel. 
The salient characters of the Hamadryad may be thus 
enumerated :—The large postparietal plates. The enlarged 
scales in the vertebral row. (This was first noted in a stuffed 
specimen in the Leyden Museum in which the skin had been 
stretched, until, each scale being free, the exact size and form 
was readily seen.) The extreme degree to which the grooving 
is developed on the teeth ; every tooth except the fangs has one, 
and some have two and even three distinct grooves. The series 
