HERPETOLOGY OF JAPAN. 467 



Formosa. Nevertheless, it is possible to trace the origin of this form 

 also to the eastern Himalayan region, as its nearest and apparently 

 quite close relative is T. monticola wliich ascends to 8,000 feet in the 

 Himalayas and extends east into China at least as far as the prov- 

 ince of Szechuen. That this species, or closely allied forms, have 

 not as yet been found in Formosa and the intervening territory 

 is not so surprising when we consider how little we know of the 

 fauna of this region, and I have but little doubt that such a link 

 connecting the habitat of T. monticola and T. oMnavensis will be 

 discovered some day. 



Reverting to the T. mucrosquamatus-elegans-Jlavovindis group, it 

 is evident that wliile T. elegans is geographically intermediate it is 

 not so located systematically and plwiogenetically, but that this form 

 and T. fiavoviridis have developed independently and in several 

 respects in opposite directions — from T. mucrosquamatus — in other 

 words, that in extending eastward and northward after having 

 reached Formosa, the ancestor of T. fiavoviridis did not invade the 

 central Riu Kiu group (Okinawa-Oshima) by way of the southern 

 (Yaeyama) group. The difference in the geological structure of 

 these two groups, as demonstrated by Doctor Yoshiwara recently, 

 probably accounts for this apparent incongruity, as their connection 

 with Formosa ma}^ have occurred at different geological periods. 



TRIMERESURUS MUCROSQUAMATUS a (Cantor). 



1839. ? Trigonocephalus mucrosquamatus Cantor, Proc. Zool. Soc. London, 1839, 

 p. 32 (type-locality, Naga Hills, Assam). — Trirneresurus mucrosquamatus 

 GuENTHER, Rept. Brit. India, 1864, p. 390 (type lost). 



1870. Tiimeresurus mucrosquamatus Swinhoe, Proc. Zool. Soc. London, 1870, 

 p. 411, pi. XXXI (Formosa). — Fischer, Abh. Naturw. Ver. Hamburg, IX, 

 1886, No. 6, p. 18 (South Formosa); Jahrb. Wiss. Anst. Hamburg, V, 1888, 

 p. 21 (South Formosa). — Boulenger, Fauna Brit. India, Rept., 1890, 

 p. 428 (Assam; Formosa). — Stejneger, Journ. Sci. Coll. Tokyo, XII, 

 Pt. 3, 1898, p. 225 (Taipa, Formosa). — Lachesis viucrosquamatus Bou- 

 lenger, Cat. Sn. Brit. Mus., Ill, 1896, p. 552 (Formosa). — Wall, Proc. 

 Zool. Soc. London, 1903, p. 99 (Formosa). 



Cantor's original specimen which came from Naga Hills, Assam,'' 

 has been lost, and no specimens from that locality have been recorded 

 since. As the description is exceedingly brief it is consequently not 

 absolutely certain that the Formosan specimens have been cort-ectly 

 identified as T. mucrosquamatus. However, the number of ventrals 

 and subcaudals, respectively 218 and 91, agrees very well, and in 

 view of the close relationship of many Formosan snakes with those 



o Signifying mucro, a sharp point, squamatus, scaly; hence, with pointed scales. 



& Boettger (Off enbach. Ver. Naturk. 26-28 Ber., 1888, p. 153) suggests a confusion 

 with " Nafa Hills," Okinawa shima, in which case Cantor's ~^.me would antedate 

 Hallowell's T. flavoiiridis. There is not the slightest probability, however, that 

 Cantor had any Riu Kiu specimen before him. 



