Say on Herpttology. 261 



fear. In my anxiety to secure him, he eluded my grasp, and 

 by a sudden and rapid exertion, disappeared, with all the rapi- 

 dity of movement so remarkable in the constrictor. This last, 

 from his celerity, is known in many districts by the name of 

 Racer. 



Coluber heterodon. This viperine species, of which Latreille 

 has formed a genus under the name of Heterodon, varies con- 

 siderably in its markings, and like most of our serpents, is not 

 constant in the number of its plates and scales, (126, 48 — 

 138, 42 — 141, 42, &c.) perhaps too much reliance has been 

 placed upon colour, and upon the number of the plates and 

 scales beneath the body, of the OphidicB generally. In the 

 form of the anterior termination of the head, the heterodon is 

 remarkable, and a good specific character may be obtained 

 from the orbital scales, which are eleven or twelve in number ; 

 the parabolic curve which passes through the eyes, and ter- 

 minates at the maxillary angles, is also generally present. This 

 same serpent was figured in Deterville's ed. of Buffon, under 

 the name of Coleuvre rtnnelee. The heterodon abounds in 

 many sandy situations, and near the sea-shore. Several per- 

 sons pursuing a pathway, passed within a few inches of one of 

 them without his betraying any emotion, but the moment he 

 perceived me advancing with my eye fixed upon him, he with 

 a sudden exertion assumed a defensive attitude, by elevating 

 the anterior portion of his body, flattening his head, and 3 or 

 4 inches length of his neck ; these he waved with a steady and 

 oblique motion from side to side, uttering at the same time an 

 audible sibilation, he made no attempt to escape, and seemed 

 absolutely fearless until taken. They have the habit of the 

 vipera, but not the fangs. It seems to be synonymous with 

 Coluber simus. This species is often called mockesoti. Dr. 

 Shaw's description of Boa contortrix seems to indicate this 

 species. Was he deceived by ^n erroneous reference to 

 Catesby's figure of this Hog-nose ? or by Forster's catalogue ? 



Coluber punctatus. A good diagnostic character of this species, 

 in addition to the cervical cestus, rests in the tripple series of 

 abdominal dots ; but these are often wanting or obsolete in the 

 young specimen, in which state it is probably the torquatus of 



