OCR Text |
Show 502 MR. G. A. BOULENGER ON THE [May 18, number, one or two, of canthal scales as a specific character, I have divided accordingly the specimens in the following table. One, which is here figured, defies the system in being referable to the first category on the right side, to the second on the left. Fig. 3. Head of Sceloporus formosus from Costa Eica. I have placed it last in the first division. It will be seen that the character is not constantly correlated with any other, and for that reason I must refuse to attach any special importance to it. Of S. Irazuensls, Giinther says :-" T w o canthal scales, but owing to the shortness of the snout the anterior is not always fully developed." I cannot account for such a statement; there is no correlation between the number of canthals and the length of the snout, as may be seen from the specimen figured above, one of the types of S. irazuensls. Giinther himself does not seem to have had great faith in the value of the character, as he has in several instances associated in the same species individuals with one canthal and others with two, although those exceptions are not alluded to in his descriptions. Curiously, Giinther's S. smarag-dlnus is described as with one canthal scale (p. 69), and yet S. tceniocnemis, Cope, is referred to it as a synonym in spite of Cope attributing to it two canthals. A. One canthal shield. a. d- S.Mexico. Godman (1) b. d- Coban, Guatemala. Salvin (2) c. J1. Duefias, Guatemala. Salvin (3) a. ($. „ „ „ e. d1- n ii ii /• O • it ii ii g- S- ., h. 2- » » .. ••• k. 2- » .. » - I. d- Ysabal, Guatemala. Salvin (3)... n. Q. 1. 84 74 85 85 75 66 66 85 66 64 84 63 57 2_ 16 15 18 17 15 14 14 16 13 13 16 13 13 3. 18 17 20 19 17 15 15 18 14 14 17 15 14 4. 17 15 19 18 16 15 15 16 13 14 17 13 13 5. ? 21 23 24 22 20 19 22 18 19 24 19 17 6. 35 35 41 42 44 38 41 40 39 40 40 34 35 7. 8 8 9 9 8 9 10 8 8 9 8 8 8 8. 40 40 50 52 50 48 48 48 48 50 44 40 38 9. 14-14 15-15 14-13 16-15 16-15 15-16 13-14 16-15 16-16 16-16 15-16 14-14 13-12 (1) Referred by Giinther to 8. irazuensls. (2) Referred by Giinther to S. lunan. (3) Referred by Giinther to S. smaragdinus. |