1881.] 



ON AMPHlSBiENIANS ETC. FROM SOCOTRA. 



461 



3. Descriptions of the Araphisbsenians and Ophidians col- 

 lected by Prof. I. Bayley Balfour in the Island of 

 Socotra. By Dr. A. Gunther, F.Z.S. 



[Eeceived March 7, 1881.] 

 (Plates XL., XLI.) 



The Reptiles described in the present paper are of considerable 

 interest. We might have expected, from the geographical position of 

 Socotra, that the species would show a close affinity to, if not identity 

 with, those of the nearest portion of the mainland of Africa ; but 

 in fact this affinity is overbalanced by that to the Arabian fauna, at 

 least as far as the few species enumerated here are concerned. The 

 most singular fact is that three out of the four species seem to be 

 peculiar to the island, two being so much differentiated as to deserve 

 generic distinction. 



1. The Amphisbsena belongs to a distinct genus, the nearest aUies 

 of which inhabit Eastern and Western Tropical Africa. 



2. The CoronelHne Snake, Bitypophis, belongs to a distinct genus, 

 apparently approaching the circum-Mediterranean Tachytnenis vivax. 



3. The Socotran species of the circum-Mediterranean or Central- 

 Asiatic genus Zamenis is most nearly allied to the Arabian Z. ele- 

 gantissimus. 



4. Finally, the Viper of Socotra is identical with a species hitherto 

 found in Arabia and on the shores of the Dead Sea. 



Allied to BaiMa and Geocalamus^ 



A. Amphisb^nid^. 

 Pachycalamus, g. n. 



Head very short, with de- 



Head-shields of Pachycalamus brevis. 



pressed snout. Rostral large, with cutting anterior edge. Two 

 large frontals form a suture together behind the rostral, and are 

 succeeded by a single very large shield, which represents the vertical 

 and occipitals. Nasal small, above the first and second labials, com- 



'■ Ann. & Mag. Nat. Hist. ser. 5, vol. vi. p. 234 (1880). 



