286 



Memoirs of the Indian Museum. 



[Vol.. I, 



The pharynx Hes in the region of the head. Its walls are composed of tall 

 columnar epithelium and it is chiefly remarkable for the peculiar poison fang which is 

 situated in its ventral wall. It can doubtless be everted by the same muscles which 

 presumably also introvert the head. 



The poison fang (text-figs, i — 3). The base of this organ is attached to the ex- 

 ternal surface of the pharynx by muscles, the point projecting freely into the pharyn- 

 geal cavity and being directed away from the mouth. It is constructed of two carti- 

 laginous bars (text-figs, i — 3, cart.) which diverge somewhat at the base, but near 



-n.c. 



ph. gl 



Fig. I. — Transverse section through the pharynx, to show the cerebral ganglia, lateral nerve 

 cords and poison fang, x 140 : cart. = cartilage ; e.g. — cerebral ganglion ; n.c. - lateral nerve cord ; 

 ■p.gl. = poison gland : fh.gl. = pharyngeal gland. 



the point come together to form a hollow tube. This tube, which is the exposed por- 

 tion of the tooth, is covered by a sharp-pointed chitinous cap, the analogue of the 

 enamel of the mammahan tooth (text-figs. 2 and 3, chit.). A tubular gland with a wall 

 composed of a single layer of flat cubical epithelium lies between the cartilaginous 

 bars and opens close to the point of the tooth (text-figs, 2 and 3, gl.ap.). The aper- 

 ture is armed with two sharp cutting edges (text-fig. 2, ce.) which must inflict an 

 exceedingly nasty wound. The specific name of the animal is given in recognition of 

 the dagger-like character of this organ. 



