ANATOMY OF THE OPHIDIA. 385 
shallow cells change rather suddenly to the type of those in the 
lung. The trachea ceases abruptly at a point just posterior to 
the heart apex. The right lung is lined with pulmonary tissue 
to about the 44th g. There is a free apex 1-5 mm. in lengt). 
There is a rudimentary left lung, a mere sac without air-cells or 
an opening into the trachea. 
The external landmarks of the principal viscera in terms of 
gastrosteges are as follows :— 
Gastroste ges) ey ecsewet cen ess 147 100 per cent. 
inlieambhape xeaeeebe ses 2 ome cen 29 19:5 
JRIGRETSS WYO)» Beoecins soneM tare Ae? 36 25:7, 
Bhi t) MEYOGL Acie ores ree ee 64 50°7 
GalllEbladder gees. 5-210: 76 55-7 
Tk rainy, TEMG, 18)0) coogsosancsacc= 119 76°5 
ssp datOT aN lita Sac ee he Hitt 128 87 
= Vente bi wes teense 126 82°7 
. shi ACTING SA a aati sin ad Laz 93 
ihe -czecalllavall Vie rsecon cree cite 128 85:5 
There are 19 scale-rows anteriorly ; at the level of the gall- 
bladder the IV row is dropped, leaving 17 rows which are 
continued to the vent. 
TROPIDONOTUS SAUTERI Boulenger. 
Specimen.—California Acad. Sci. No. 18988. Kanshirei, 
South Formosa. Adult female. 
The tracheal membrane begins to be lined with respiratory 
tissue a little anterior to the base of the heart. The trachea 
enters the lung at the level of the 24th gastrostege. The right 
lung is lined with respiratory tissue to the 55th g. There is 
a free apex about one and one-half gastrosteges long, in rela- 
tion with the right side of the trachea. The rudimentary /ef¢ 
lung is at the 25th g.: it is a mere fibrous sac, 2 mm. long, 
without pulmonary tissue. The heart apex is at the 24th, and 
the tip of the liver at the 32nd g. 
Thereare 17 rows of scales anteriorly and the same posteriorly. 
Gastrosteges 128. 
PSEUDOXENODON SINENSIS Boulenger. 
Specimen.—Brit. Mus. Nat. Hist. Ex. No. 713-18. Yunnan 
Fu, China. Adult male. 
The tissues in this specimen are in too fragile a state to permit 
of a satisfactory autopsy. The tracheal membrane is developed as a 
broad thin sheet; the air-cells begin at the 28th g. The carti- 
laginous rings are broader and thinner than in most species. 
There is a cervical set of air-chambers above and to the right of 
the trachea ; these are divided into about seven compartments by 
transverse partitions. Each compartment opens into the trachea 
by a large round foramen situated on the tracheal membrane; 
these are opposite the following gastrosteges: 3, 7, 11, 15, 19, 
