Maccall's Horned Lizard

Phrynosoma maccallii, (Hallowell)

Colouration: Ashy-gray; a narrow, brownish line upon the back; on each side this are two rows of round, brown spots each containing a paler centre, which in turn is centered with a brown dot.
Dimensions: Total Length . . . . . 3 3/4 inches.
Distribution: The Colorado Desert. The United States National Museum has specimens from Fort Yuma, Arizona. It appears to be a very rare species.
Habits: Nothing is known of the habits.

The last lizard of this genus is of rare occurrence. It has the longest head spines of any of those species with concealed ear-drums. There are two series of spiny, marginal scales on the body, the upper of which is the longer. In the central region of the chin are two single rows of slightly enlarged scales. The scales of the abdomen are smooth. The skin of the back appears very smooth as compared with other horned lizards.

The head spines are peculiar. There are two very large central spines; only the two rear spines of the temples are large--this in place of the three successively larger temporal spines of most species.

Length of Head and Body . . . . . 2 13/16 inches.

Width of Body . . . . . 1 5/16 inches.

The desert fauna of the United States is not only distinct, but highly interesting. One of the most fascinating exhibits in the reptile house of the New York Zoological Park, is the "desert room." Here, even the most casual observer will at once note something peculiar about the lizards and the snakes--their pallid hues, their remarkable similarity to the sand and their adaptability to the dry, loose soil, in their movements of burrowing or progressing at great speed over a surface where many reptiles would be clumsy. At a temperature in which some reptiles thrive, these creatures of the deserts are sluggish. They flourish and are most active in a heat that is practically unendurable to the human. This phase of reptile life is worth much space--much more than can be given to it in the present work.

CHAPTER XVIII: THE PLATED LIZARDS AND SNAKE-LIKE SPECIES

The Families ANGUIDAE and ANIELLIDAE, Embracing the North American Genera GERRHONOTUS--Plated Lizards; OPHISAURUS--Glass "Snake" and ANIELLA--Ground "Snake."

FAMILY Anguidae; the Plated Lizards and Glass "Snakes:" With this family, the student is referred to a group of degenerate lizards, all of which are elongate and serpentine in form, and either possess small and rather weak limbs, or are externally wholly devoid of these organs. The latter species are often mistaken for snakes, which is a natural consequence, owing to the methods of progression and the serpentine outlines, in every way appealing to the snake rather than to the lizard. There are forty-four species of this family; they inhabit both the New and the Old Worlds. They are most abundantly represented in Mexico and in Central America. The species are characteristic from the presence of a deep fold on each side of the body.

The Plated Lizards; Genus Gerrhonotus: The body is slender, with large, square scales above, arranged in regular, ring-like rows; with most of the species, the scales of the middle portion of the back are strongly keeled.

Along each side of the body, from behind the ear to the base of the hind limb, is a strip of soft flesh, containing small, granular scales; against the lower border of this strip, the edge of the abdominal sheet of scales fits loosely, forming a deep fold.

The head is distinct from the neck and pointed at the snout. The limbs are rather small and the tail very long and brittle--frequently twice as long as the head and body.

Four species of this genus inhabit the extreme western and southwestern portions of the United States. Nineteen species are recognised, the greater number occurring in tropical Mexico and Central America.

Like many other genera among the reptiles these lizards have encountered a share of the undue enthusiasm displayed in founding new species and sub-species upon variations that are of little importance. There has been a number of species described as occurring in the United States and the descriptions of them have been based upon slight differences of scalation and distribution. If these obscurely different specimens were mixed among varying individuals of the really staple species and the locality labels removed, it is doubtful if the observers of their "distinctly" different characters could pick them out again. Thus it appears that the different species described as occurring in the United States must simmer down to four, a key of which is herewith presented:

I. Three shields arranged in triangular fashion, in front of the large shields between the eyes.

Scales of the back and the sides strongly keeled.

KEELED LIZARD, G. multicarinatus.

Habitat.--Widely distributed. The Pacific Coast region, from British Columbia to Central America.

Scales on the back strongly keeled; those of the sides smooth. BROWN LIZARD, G. liocephalus.

Habitat.--Texas and Mexico.

Scales of the back feebly keeled; those of the sides smooth. KING'S LIZARD, G. kingii.

Habitat.--Arizona, New Mexico, western Texas and northern Mexico.

II. Three pairs of shields in front of the large shields between the eyes.

Scales of the back keeled; those of the sides smooth.

PLATED LIZARD, G. imbricatus.

Habitat.--Western Texas; Mexico.

Detailed descriptions of these species follow: