24. TKACHTSCHIUM. 297 



2. Hydrablal)es prsefrontalis. 



Ablabes periops, var. praifrontalis, Moc(p(ard,Le Natur. 1890, p. 154, 

 and Nouv. Arch. Mm. (3) ii. 1800, p. 137, pi. ix. fig. 1. 



Hydrablabes piwfroutalis, Bonlewj. Ann. 8f Max/. N. II. (6) vii. 

 1891, p. 344. 



Distinguished from the preceding by the fusion of the prscfrontals 

 into a single shield, and 15 rows of scales. Ventrals 178-180. 

 Olive-brown above, with two pairs of blackish longitudinal streaks. 



Kina Baloo, North Borneo. 



24. TRACHISCHIUM. 



Trachischium, Gilnth. Cat. Col. Sn. p. 30 (1858) ; Bonleny. Faun. 



Ind., Rept. p. 284 (1890). 

 Ablabes, part., Gunth. Rept. Brit. Ind. p. 223 (1864). 



Maxillary teeth 18 to 20, subequal ; posterior mandibular teeth 

 shorter than the anterior. Head not distinct from neck; eye small, 

 with vertically subelliptic pupil ; nostril between two small nasals ; 

 prsefrontals sometimes united. Body cylindrical ; scales smooth, in 

 13 or 15 rows, without apical pits ; ventrals rounded. Tail short ; 

 subcaudals in two rows. Hypapophyses developed throughout the 

 vertebral column. 



Eastern Himalayas and Khasi Hills. 



Synopsis of the Species. 



I. Scales in 13 rows, those of the ischiadic region keeled in the 



males. 



Praefrontal shield usuall}' undivided ; one 



postocular ; 150 ventrals or more 1. fu,<}eum, p. 297. 



Praefrontal shield usually undivided ; one 



postocular ; 132-145 ventrals 2. (jueniheri, p. 298. 



Two praefrontals ; two postoculars 3. tenuiceps, p. 299. 



II. Scales in 15 rows, all smooth. 



Sixth upper labial largest 4. monticola, p. 299. 



Last three upper labials subequal 5. rubrivcnter, p. 300. 



1. Trachischium fuscum. 



Calamaria fusca, Blyth, Journ. As. Soc. Beng. xxiii. 1854, p. 288. 



obscuro-striata, Blyth, I. c. 



Trachischium rugosum, Giinth. Cat. p. 30 (1858). 



fuscum, Giinth. Proc. Zool. Sac. 1860, p. 161 ; Thpnh. Cat. liept 



As. Soc. Mus. 1868, p. 45 ; Ander.^. Proc. Zool Soc. 1871, p. 171 \ 

 Theob. Cat. Bept. Brit. Ind. p. 144 (187G) ; Boulenn. Faun Ind " 

 Bept. p. 285 (1890). 



Ablabes fuscus, Giinth. Rept. Brit. Ind. p. 225 (1864). 



Rostral as broad as deep or a little deeper than broad, visible 



