366 Coe and Kunkel— California Limbless Lizard. 
shape, subhexagonal or cycloidal and strongly imbricate and arranged 
in from 26 to 32 longitudinal rows, 30 being the usual number ; the 
margins are entire and the surface smooth. 
There are five preanal scales (text-fig. 12), of which the median 
one is the longest and more or less wedge-shaped with its apex pos- 
terior. The lateral scales are subequal and lozenge-shaped. 
Some embryos just previous to the time of birth showed several 
interesting variations from the adult type. The interparietal plate 
13 
Figure 12. Arrangement of scales Figure 13. Arrangement of scales of 
about cloacal aperture of adult. x4. body, seen from left side. x4. 
of the embryo is much broader relatively than in the adult and the 
posterior margin of the fronto-frontoparietal is more rounded in its 
contour than in the adult (pl. xxu, fig. 11). The interparietal 
also showed considerable variation in size, for in some cases it was 
not only relatively but also actually larger than in the adult. In a 
single embryo the parietal in contact with the interparietal on the 
right was replaced by three small cycloidal scales which occupied 
approximately the same space that the single parietal on the left did. 
Of these three the anterior was the largest and the posterior one was 
the smallest and overlapped the occipital more than did the parietal 
on the left. 
The position of the pineal eye with reference to the interparietal 
plate shows much variation in these embryos ; usually it is in the 
anterior portion, but it may lie centrally or even posteriorly. In the 
adult, on the other hand, the pineal eye always lies entirely in the 
anterior portion. The eye can be seen clearly beneath this plate, for 
there is a circular unpigmented area directly above it with a diameter 
about twice that of the underlying structure (fig. 10), so that the eye 
appears as a perfectly black spot surrounded by a pigmentless area 
which blends off into the general color of the dorsal side. 
Dermal Ossifications.—Dermal ossifications are strongly devel- 
oped, underlying each scale. They are usually palmate in form 
