560 



SLENDER HYDRUS. 



Hydrus Gracilis. H, corpore anterius gracilUmo sqmmis watia 

 lavibns, posterius crassiore squamis hexagonis abrupte truncatis, 



Hydrus with the fore part of the body v^ry slender, and co- 

 vered with smooth ovate scales ; the hiiid part thicker and 

 covered with abruptly-carinated hexagonal scales. 



Length about two feet: head very small, or 

 not of greater diameter than the neck, and co- 

 vered with large scales : neck and fore part of the 

 body very slender, not more than about a fifth of 

 an* inch in diameter, and cylindric for the di- 

 stance of about seven inches, when it begins to 

 enlarge and flatten into a carina on the upper 

 part, which is continued to the end of the tail. 

 The slender part above mentioned is covered 

 with ovate smooth scales ; the remainder of the 

 animal with hexagonal ones, each marked with an 

 abrupt central carina: the tail is about an inch 

 and three quarters long, flat, and obtusely-acumi- 

 nated, but not so broad as the thickest part of the 

 body: its lower edge is less carinated than the 

 upper, the row of hexagonal scales of the abdomen 

 being continued on this part to the tip. The co- 

 lour of the whole animal is now grown pale, but 

 appears to have been banded all along the upper 

 parts fiom head to tail with numerous, equidistant 

 brown and somewhat obtusely pointed bands reach- 

 ing almost to the abdomen, those on the small or 

 cylindric part of the body being continued into 

 annuli : the stricture or contraction at the place 



