428 Dr. A. Giinther on Psammophis Perroteti. 
and shorter teeth. The spinous process of the body is of extra- 
ordinary length; the caudiform appendage, which is still but 
little developed, terminates in a pointed extremity bent upwards. 
The length of the larva is 3 millim. 
EXPLANATION OF PLATE VII. 
Fig. 1. Larva, probably of a Balanide, seen from above. Of the swim- 
ming feet, only the middle pair and one of the anterior are seen 
extended: a, carapace; 6 b, horns of the carapace; c, eye; 
d, spinous process of the body; e, caudiform appendage of the 
ody. 
Fig. 2. Very Jae larva of a Cirripede, probably a Lepadide; from the 
back : a to e, as in fig. 1; f, alimentary canal. 
Fig. 3. A portion of the body of the larva of Lepas anatifera after the 
first moulting, strongly magnified: a, central mass of the nervous 
system; 5, ocellus; cc, the two horns of the carapace. 
LIV.—Note on Psammophis Perroteti, D. & B. 
By Dr. Abert GinTHER. 
[With a Plate.] 
Dumerit and Brsron have omitted several important characters 
in their description of this remarkable snake, which is a truly 
intermediate form between Psammophis and Dryophis. One of 
its most important characters appeared to me to be the keeled 
scales of the coccygeal region *; but as nothing of it is men- 
tioned by the French herpetologists, I failed to recognize the 
first specimens which came under my observation, and described 
them as a new species—Dryophis tropidococcyx. The latter 
specific name has been chosen with the view of its serving 
as the name of the genus, if the snake should be considered as 
a peculiar type. It cannot be referred either to Psammophis or 
to Dryophis without disturbing the natural characters of those 
genera; whilst, as a separate genus, it may be placed in the 
family of Dryophide, the characters being rather more in favour 
of its relation to this family than to the Psammophide. 
Tropipococcyx. 
Habit and physiognomy of Psammophis. Scales smooth, 
those of the coccygeal region keeled. Rostral shield far pro- 
duced backwards. A single nasal, pierced by the nostril ; pos- 
terior nasal and loreal absent, replaced by the anterior and 
posterior frontals, which are bent downwards on the side of the 
head. Pupil horizontal (Dryophis). The fifth of the anterior 
maxillary teeth and the hindmost longest, the latter grooved. 
* A similar peculiarity occurs in Aspidura trachyprocta, Cope, and 
Trachischium, Gthr. 
es Na i Nn 
