12 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 



SCINCIDAE. 

 Cryptoblepharus poecilopleurus. 



Figs. 7-12. 



Ablepharus poecilopleurus Wiegra., N. Act. Caes. Leop., 1835, vol. 17, 202, pi. 18, 



fig. 1. 



Cryptoblepharus poecilopleurus Wiegm., 1. c, 204. 



Excepting in the tendency to vary there appears to be little by which we can 

 separate Easter Island representatives of this species from those taken on certain 

 of the Hawaiian Islands. The latter are regarded as typical of the species. 

 Originally the description was drawn from an individual secured on the islands near 

 Pisacoma, Peru; it in all probability was, like the one reported by Boulenger 

 from Bahia, Brazil, an accidental or a descendant of one that had been carried far 

 from the home of the species. C. poecilopleurus is likely to have sprung from 

 C. boutonii and to have originated in or near the Hawaiian Islands. The parent 

 form possessed a smaller number of rows of scales and had but four labials in 

 front of each suborbital ; or, in a general way, it had a smaller total number of 

 scales on the individual. C. nigropunctatus from the Bonin Islands stands closer 

 to C. boutonii ; its scale rows number from twenty-four to twenty-six, and it has 

 but four labials. A large specimen of this form measures about five and three- 

 fourths inches in total length, the body two and one-eighth ; the lateral streaks 

 are very indistinct and the entire upper surfaces are freckled with brown and with 

 silvery white. A couple of specimens from Wake Island must also be placed 

 among those nearer C. boutonii. Their differences from one another are of enough 

 interest for description here : — one of them has twenty-eight rows of smooth 

 scales and has no supranasals between the internasal and the nasals ; the other has 

 twenty-six rows of faintly grooved scales, has a supranasal on each side, formed 

 by a longitudinal division of the nasal, and has the tail forked near the end in 

 such a manner as to make it appear that the deformity was congenital ; each of 

 them has four labials. From these localities southward the number of scale rows 

 decreases. It is to the southwest that the species with fewer rows of scales 

 predominate, the numbers decreasing until on C. rutilus there are but twenty. 

 More distant allies from West Australia have sixteen rows and three labials. 

 C. eximius from Moala and Naikobu, of the Fijis, has twenty-two rows of scales 

 and four labials. C heterurus from Gilbert Islands exhibits a variational tendency 

 similar to that of C. poecilopleurus from Easter Island, but it has a smaller number 

 of rows of scales. Comparing nine specimens from the latter locality with the 

 same number from the Hawaiian Islands, it will be seen that a slight divergence 

 has set in which continued, with isolation, selection unnecessary, for a sufficient 

 period will account for a new variety and eventually a new species, an offshoot 

 from C- poecilopleurus. Eight of the nine from Easter Island have 28 rows of 

 scales each, one has 30 ; two have 4 labials on each side, five have 5 on each 



