OCR Text |
Show 1906.] IN MEXfCAN LIZARDS. 341 of granules at the hinder edge. Posterior side of forearm with large scutes in at least one row.-Consequently these specimens combine the intensified features of the C. gularis group. The immature have 6 clear whitish stripes, and faint brownish spots in the very dark, almost black first and second fields. The centre-field 3-3 is also black, with a short white centre streak on the nape and neck, and this streak is in one specimen continued upon the back by a double row of pale spots ; in another it is continued as a dull impaired stripe. These variations demonstrate the possibility of 7 to 8 stripes in all.-In the 88 m m . specimen all the stripes are reduced to faint lines on the neck. The rest of the back shows a uniformly black ground with numerous whitish spots in about 10 rows ; the thighs are similarly spotted. In the oldest specimen (97 mm.) the ground-colour is very dark, blackish, with numerous, very conspicuous white and bluish round spots in 10 or 11 rows. The three pairs of stripes are faintly visible on the neck, where the spots are far less pronounced. Throat and collar are pink. Rest of under parts, including the arms, blue-black, mottled with particoloured scales. Tail bluish beneath. This 97 m m . specimen much resembles a 90 m m . specimen from Lerclo, near Torreon ; this town would, with our present state of knowledge, represent the North-eastern limit of the typical C. communis. The collar of the Lerclo specimens is composed of large scales, without granules. Throat of the adult red-pink ; sides of collar grey. Rest of under parts, including thighs, blue-black with whitish scale-edges. Tail bluish.-Above : the smaller specimen with 6 complete stripes and a pale centre-line. Double rows of grey-brownish spots in the dark fields. In the larger specimen the stripes have disappeared completely; ground-colour black, with numerous bluish-white spots, arranged in rows, from neck to tail. Sides of trunk with black and light bars, some of which reach far upon the back. Ixtlan.-The specimens were collected by Dr. Buller near the River Santiago, near the confines of the State of Jalisco and the Territory of Tepic, at altitudes from 1500 to 3500 feet. This district is sandy, rather tropical, and produces much vegetation. It is remarkable that none of these specimens belongs to the essentially spotted-colour variety, but ends in the partly cross-barred type. The evolution of the dorsal pattern proceeds as follows :-They start with 6 to 8 pale stripes and black-brown fields. Pale, light-brown spots in one or two rows appear in all the fields, proceeding from behind forwards. Against the inside of the third pair of stripes appears a double series of blackish spots. Stripes 2 and 3 become dull, and within each of these stripes appear, or remain, white spots. The field-spots become pale, buff or whitish, and then they become transversely confluent within each field. Ultimately alternate black and whitish cross-bars are produced, which, reaching from the flank through stripe 1, through field I., through stripe 2, cause a cross-barred appearance. This procedure much resembles that of the typical C. mexicanus. 23* |