ANATOMY OF THE OPHIDIA. 397 
series, 2. e. one, No. IX, was next to the median row, and the 
other, No. IV, was on the flank. 
The scale formula of over one hundred species has been studied 
and the serpents possessing the non-adjoining type have usually 
been in the Dipsadomorphine. The following were the excep- 
tions :—Loodon lineatus Dum. & Bibr., Zamenis rhodorhacis, Jan, 
4. florulentus Geoff., and Coluber oxycephalus Boie. 
This species is common in the vicinity of Manila, where it 
inhabits the brackish water swamps that border the Bay. Over 
a score have been seen in shallow places resting or moving slowly 
on the bottom. They are able to remain beneath the surface for 
several hours at a stretch. This may explain the need of the 
extensive respiratory area in the trachea and lung. 
LEPTODIRA HOTAMB@IA Laurenti. 
Specimen.—Brit. Mus. Nat. Hist. Ex. No. 713-10. Fort Hall, 
British Hast Africa. Adult male: total length 950, tail 85 mm. 
The trachea terminates at the 34th gastrostege; it ends 
abruptly, and the only trace of an intrapulmonary continuation 
is in a regular arrangement of the air-cells in an imaginary line 
in its prolongation. The tracheal membrane begins near the 
glottis on the left side; further on it winds to the dorsal side of 
the tube, and at the level of the 28th g. it becomes lined with 
shallow air-cells. The right lung is reticulate to the 47th g. 
The left lung, 2°3 mm. long, is at the level of the apex of the 
heart; it is closely adherent to the left side of the pericardium, 
and opens into the trachea at the 33rd g. 
The vertebral artery arises from the right arch at the 29th 
gastrostege, and is superficial to the 18th; it gives off five 
branches, all of which enter in the median line. The gastro- 
stege level of these branches is as follows :—I.-27; I1.-26; 
IIT.-23; 1V.-22; V.-20. 
The right aortic arch joins the left at the 38th gastrostege ; 
at the 31st it gives off a single intercostal branch, which bifur- 
cates close to the entrance in the median line, one fork supplying 
each side. The intercostals from the anterior part of the dorsal 
aorta enter in the median line. 
The external landmarks of the principal viscera in terms of 
gastrosteges are as follows :-— 
Gastrostesesh ease te ce 163 100 per cent. 
team bua exce yaa ite tnee eae rele 34 20:9 
vers, bio Mee saree feecee ars a 4] 25°2 
pict) (8) ONC CBr eae MPRA ORT RAR 81 A9°7 
Gall-bladdemeywyes, aes 1590 553 
TEGiC hares, TAEINE SM co ceonensgencoe 129 80 
aA PAE TiC) eh sk 2 155 95 
Himlehty! tuoi Weck eine 136 83°5 
MCP, sae. ee sme. 156 95:7 
oP) 39 
The number of scale-rows on the body, the sequence in which 
