AKT. 12 REVISIOlSr OF LIZARDS OF GENUS CTENOSAURA BAILEY 15 



Shaw. Again he assigns no reason for changing the name of a species. 

 Fortunately, however, neither of his last two species were ever recorded 

 as distinct, the "law of priority," although not known as such at that 

 tune, having taken care of the situation. 



In 1886 Cope published the description of Ctenosaura multispinis,^^ 

 based upon an adult male dried skin from Dondominguillo {Dondom- 

 ingville), Oaxaca, Mexico. A careful examination of this specimen 

 and comparison with others indicates very conclusively that it is 

 merely a "dark phase," or mature individual of acanthura. As a 

 matter of fact the large specimens of acanthura are commonly known 

 as black ctenosaurs. 



Perhaps the most interesting observations made on this species are 

 recorded by Ditmars.^^ He says: 



The old lizards are generally uniform jet black with marblings of olive or even 

 exhibiting reddish blotches. They are surly brutes, immediately showing fight 

 when cornered, not only endeavoring to bite, but dealing ugly blows with the gener- 

 ously spiked tail. From painful experience the writer (Ditmars) can testify that 

 a blow from the spiny tail is capable of producing a severe laceration. If an 

 avenue of escape is open, most specimens prefer flight to combat. If discovered 

 while sunning in their favorite position, on top of a rock in a forest opening, the 

 creature hurls himself into the shrubbery making as much noise as a frightened 

 cow, as it goes away to a considerable distance. This species is not much in the 

 habit of ascending trees; it can, however, climb fairly well. On the ground it is 

 very fleet, running with the body high, the tail slightly elevated. A strong lizard 

 can easily outrun a man as to speed, invariably escaping by darting into a thicket. 

 Very young specimens are uniform, bright emerald green. They are persistently 

 terrestrial, running on their hind legs in kangaroolike fashion when frightened. 

 Observations made in large yards with a number of species of lizards, however, 

 have demonstrated to the writer that the habit is prevalent among many of the 

 long-bodied lacertilians of both the Agamidae and the Iguanidae. He has thus 

 far noted the habit among 10 genera. It seems probable we have here a heredi- 

 tary character, handed down from gigantic reptiles of the past, for several of those 

 creatures, now known only by the ponderous fossils imbedded under mountains 

 of rock, were constructed to stalk about on their powerful hind legs. 



In its natural environment acanthura is thought of as being strictly 

 vegetarian in its diet, but the dissection of many stomachs shows that 

 it also is very fond of insects. 



Harlan ^^ observed that a specimen living in the Philadelphia 

 Museum for several months ate nothing of its own accord, but that 

 when raw meat or fruit was placed in its mouth, would swallow it 

 leisurely without chewing. He showed a preference for raw meat, 

 and always rejected cooked meat. During the summer the speci- 

 men subsisted chiefly on fruit and was never observed to drink. 

 During the autumn (November, 1824) he became considerably torpid, 

 remaining in one position for hours, without any disposition to move 

 unless roused, when he displayed considerable activity. He became 



fe^'i Cope, E. D. Proc. Amer. Philos. Soc. Phila., vol. 23, p. 267, 1886. 



'2 Ditmars, R. L. The Reptiles of the World, p. 141, 1910. 

 L" Harlan, R. Journ. Acad. Nat. Sci. Philadelphia, vol. 4, pp. 242-251, 1824. 



