PASSERITA MYCTERIZANS. 305 



PASSERITA, Gray, 



Body and tail exceedingly slender, slightly compressed ; head depressed, 

 very long, with the snout long, pointed, and terminating in a flexible 

 appendage ; praeorbital region deeply concave, with a projecting edge above. 

 Eye of moderate size, with horizontal pupil ; nostril small, lateral, situated 

 in the hinder part of a single nasal shield. Shields of the head regular ; 

 loreal none. Scales smooth, elongate, narrow, much imbricate, in fifteen 

 rows, those of the vertebral series larger than those on the side. Ventral 

 shields not keeled ; anal bifid. Maxillary with a strong tooth in the middle 

 and with a grooved tooth behind. 



It is difficult to say whether the rostral appendage has to perforin a function similar to 

 that of the tentacles of Herpeton^ which are presumed to serve as organs of touch, in the 

 water or mud, without necessitating the exsertion of the tongue and the opening of the 

 mouth. In Passerita, which never enters the water, the tongue would appear to perform 

 its function quite as perfectly as in other land snakes ; moreover the rostral appendage of 

 Passerita is covered with tough shields, and is consequently but slightly sensitive to touch. 



Two species are known : — 



Belly with two yellow longitudinal bands P. myctei-izaris. 



Belly -Nrithout bauds P. purpurascens. 



Passerita mtcterizaxs. 



? Coluber mycterizans, L. Mus. Ad. Fried, p. 28. 



Russell, hid. Serp. i. tab. 12, 13. 



Dryinus nasutus, Meir. Tent. p. 136 (not Bell), Bum. ^c Bibr. vii. p. 809. 



Passerita mycterizans, Graij, Ann. Phil. x. p. 208. 



Dryiophis nasuta, Schleg. Phys. Serp. ii. p. 246. pi. 10. figs. 1-5. 



vScales smooth, without apical groove, those of the vertebral series rather larger and broader 

 than the others, in fifteen rows. Ventrals 172-188; anal bifid; subcaudals 140-166. The 

 rostral appendage is formed by the rostral shield, which is prolonged, foui-sided, folded ; in 

 young specimens it is curved upwards ; the nasal shields also are prolonged and form a part 

 of the lateral surface of the appendage, which is sometimes injured, when it is covered with 

 small irregular shields ; the whole length of the rostral shield equals one-half of that of the 

 snout without appendage. Occipitals pointed and divergent behind. Loreal none, replaced 



2r 



