500 M. F, Sumichrast on the Habits of some Mexican Reptiles. 



movement persists for a long time after death in this reptile ; 

 and if we may believe the relations of the Indians, it is prolonged 

 for forty-eight hours or more in the head after its separation 

 from the body. 



The colour of the spots scattered over the body and limbs of 

 Heloderma horridum is subject to variations, due to age or to 

 difference of locality. These spots pass from whitish yellow to 

 reddish brown, through a series of intermediate shades; their 

 arrangement, which is far from constant, cannot furnivsh precise 

 descriptive characters. Age likewise produces great changes in 

 the size : some individuals attain a length of nearly 5 feet. 



II. Family Ignanidse. 



Genus Iguana, Laur. 



Iguana rhinolopha, Wiegm. 



' Iguana verde ' of the Creoles. ' Guchachi-guela** of the 

 Zapotec Indians. 



Genus Cyclura, Harlan. 

 Cyclura acanthura, Wiegm. 



' Iguana negra ^ of the Creoles. ' Guchachi-cheve ' * of the 

 Zapotec Indians. 



Although the two species of Iguanidee. of which the above is 

 the synonymy belong to different genera, I have thought it 

 best to combine the facts which Thave collected upon their his- 

 tory in a single article, in order to give prominence to the prin- 

 cipal points in their organization and habits which have induced 

 the separation of the genera Iguana and Cyclura. 



Representatives of these two genera of reptiles are found over 

 a great part of the territory of the Mexican republic — that is to 

 say, in all that zone which stretches along the shores of the two 

 oceans, and is known under the name of the Tierras calientes. 

 The true Iguanas are more diffused than the Cyclura upon the 

 eastern side — a circumstance which is easily explained by the 

 fact that this part of the country, being furrowed with water- 

 courses and small lakes {lagunas) and covered with a luxuriant 

 vegetation, presents biological conditions the most favourable to 

 the animals, which prefer the vicinity of water. The Pacific 

 coast, on the contrary, is dry and sandy — a condition which 

 suits well with the more terrestrial habits of the Cyclurce, and 

 favours their multiplication. 



* These native names are literal translations of the Spanish terms 

 Iguana verde and I. negra. The Zapotec name of the Iguana is Guchachi', 

 gv/sla means green, and ch^e, black. 



