212 G. A. BOULENGER ON 
r. Length from snout to vent (in millimetres). 2. Scales and plates round middle of body. 3. 
Longitudinal series of dorsal plates and scales. 4. Longitudinal series of ventral plates. 5. Transverse 
series of ventral plates. 6. Plates in collar. 7. Gular scales in straight median line. 8. Femoral pores 
on each side. g. Iamellar scales under fourth toe. 
Habitat. South-Eastern Siberia, Manchuria, Corea. 
T. amurensts is the most Lacerta-like species of the genus, and its agreement in 
many respects with L. vivipara' is the more noteworthy for the fact that the latter 
is the only species of Lacerta which extends eastward to the Pacific Ocean.” ‘The 
agreement is not only in the form of the head and the comparatively short tail, but 
also in the shape and arrangement of the head-shields, especially those bordering the 
nostril, and the occasional separation of the fourth supraocular from the frontoparie- 
tal,’ and of the ventral shields. As the scaling of the back and the coloration may 
very well be derived from the condition in L. wivipara, I have little doubt that the 
genus Tachydromus is to be regarded as directly modified from an oriental species of 
Lacerta connected with L. vivipara, if not from that species itself. 
2. Tachydromus tachydromoides, Schleg. 
Lacerta tachydromoides, Schleg. Faun. Japon., Rept., p. 101, pl. i, figs. 5-7 (1838). 
Tachydromus japonicus, Dum. et Bibr. Erp. Gén. v, p. 161 (1839); Giinth. Rept. Brit. Ind., 
p. 69 (18604) ; Hilgend. Sitzb. Ges. Nat. Fr. Berl., 1880, p. 112. 
Tachysaurus japonicus, Gray, Cat. Liz., p. 52 (1845). 
Lachydromus tachydromoides, part., Bouleng. Cat. Liz., iii, p. 5 (1887). 
Tachydromus tachydromotdes, Giinth Ann. and Mag. N.H. (6) i, 1888, p. 169; Stejneg. Herp. 
Japan, p. 247, fig. (1907). 
Tachydromus holstt, Bouleng. Proc. Zool. Soc., 1894, p. 733, pl. xlix, fig. 1. 
Body feebly depressed. Head 1} to 13 times as long as broad, its depth equal to 
the distance between the anterior corner of the eye and the tympanum, its length 
3% to 4 times in length to vent in males, 4 to 4} times in females ; snout pointed, 
with strong canthus and nearly vertical loreal region, as long as the postocular part of 
the head. Pileus 1} to 2 times as long as broad. Neck as broad as the head. The 
hind limb reaches the axil, the shoulder, or the collar in males, the wrist, the elbow, 
or the axil in females ; foot 1 to 14 times as long as the head. ‘Tail 2 to 34 times the 
length of head and body (14 times in the very young). 
Nostril pierced between three shields. Rostral not entering the nostril, nearly 
always in contact with the frontonasal*, usually broadly; frontonasal as long as 
broad or slightly broader, as broad as the internarial space or a little broader ; 
preefrontals forming a median suture ;° frontal as long as its distance from the end 
of the snout, 1} to 2 times as long as broad, usually narrower behind than in front ; 
parietals as long as broad or a little longer than broad (up to 14), interparietal 14 to 
2 times as long as broad ; occipital small, much shorter than the interparietal, often 
| I have therefore represented details of that species on plate XLVI for comparison with T. amurensis. 
* The Easternmost specimens show, on an average, a lower number of pores (5 to 11) than the Western. 
» A character which has become fixed in T. sexlineatus, at the other end of the series. 
+ Two exceptions, male from Koshikeu and female from Koyosun, in which the nasals meet behind the rostral, 
® Sometimes separated by a small azygos shield, according to Stejneger. 
