OCR Text |
Show 302 DR. H. GADOW ON EVOLUTION [Mar. 20, CNEMIDOPHORUS SEXLINEATUS Linn. (Text-figs. 71 A, B, C ; 62 B: 65 D ; 73 A, B.) Material examined :- 4 from Raleigh, N. Carolina. 3 (1 each) from Pensacola, Florida ; Kansas ; Duval County, Texas. 2 from Bloomington, Indiana. 3 from San Diego, California. 4 from Sauz, north of Chihuahua (Coll. Dr. Meek). Definition.-4 supraoculars. Collar composed of several rows of large scales (text-fig. 65 D ) ; posterior surface of forearm with several rows of slightly enlarged granules (text-fig. 62 B). Under-parts white; 6 to 7 white or yellowish complete stripes on the back; fields dark without spots (text-fig. 71 A, B, C). Size distinctly small, up to 70 mm.; an adult $ from Sauz, with large eggs, only 57 m m. With very wide distribution in North America; from Maryland and Delaware to Illinois, Kansas, and Nebraska ; southwards to Florida, through Texas to Laredo, thence to Chihuahua, Arizona, and into Southern California. Linne's types came from Charleston, S. Carolina; Edit. xiii. p. 364: "Corpus supra utrinque lineis 3 albis angustis et totidem nigris alternis. Dorsum lineis 3 mediis interjectum, canesceus quasi ex duabus lineis albidis. Ruga; duo sub collo." Supraoculars 4 ; the posterior is separated from the parietals by one or more rows of granules, unless it is almost in contact wTith the parietals. Of the four Raleigh specimens only the largest has 4/4 complete supraoculars ! In one of 68 m m . only 3/3 ; in the other of 68 m m . (text-fig. 71 A ) the posterior is absent on the left side, on the right it is reduced to a large granule, and the anterior scute is broken up into several. The 58 m m . specimen has only 3/3, due to loss of the posterior scutes, but the anterior pair is broken up into several. Frenocular plate variable. In two Raleigh specimens present, in one absent on both sides, in one present on the left side only. Absent in all the four Sauz specimens. Collar (text-fig. 65 D).-According to Cope, " scales of collar larger, in fewT rows, the largest forming the lower." In reality the collar of C. sexlineatus is variable and closely approaches that of the C. deppei-group. Instead of the posterior edge being formed by a row of large scales, it is in many cases, at least in the centre, composed of granules only ; or there are numerous granules interspersed between the scales of the edge. The large scales themselves often decrease in size rapidly towards the sides. Cope's figure is much more to the point than his description. The .strongest collar, with an edge of large scales and but few or no granules, I find in the tw7o San Diego specimens. Humerus with 5 to 7 rows of scales, of which the first 2, 3, or 4 are considerably larger than the rest. |