CAUDAL AUTOTOMY AND REGENERATION IN THE GECKO 99 
balsam, the bichromate fixative acting as a stain for many of 
the tissues. For histology, the spirit-preserved material was 
first decalcified by leaving it in alcohol plus nitric acid for 
several weeks, and subsequently dehydrated, embedded, cut, 
and stained with haemotoxylin. for dissection of the muscles 
preliminary maceration of the tails in weak alcohol or water 
plus nitric acid gave good results. 
NotrEs ON THE ORIGINAL AND REGENERATED TAILS OF 
Sphenodon punctatus. 
I have examined the original and regenerated tails of 
Spbhenodon punctatus kindly given to me by Professor 
Arthur Dendy. The seales are arranged in the original tail in 
accordance with the planes of autotomy, each autotomy 
segment bearing dorsally one of the large mid-dorsal scales, 
and ventrally two transverse rows of the large hexagonal 
scales. The muscles, after removal of the skin, have a super- 
ficial arrangement closely resembling that of the Gecko shown 
in Text-fig. 8, E, F, only the muscles are more numerous. 
In lateral aspect, e.g., there appear to be four muscle layers 
(and processes) instead of two as in the Gecko (Text-fig. 3, F). 
In transverse section the muscles are also seen to be more 
numerous than in the Gecko, and they extend inwards from the 
skin to the vertebral column, fat bands being entirely absent. 
The muscles are separated from each other by thin radiating 
septa of dense connective tissue. I dissected out a piece of 
the caudai artery about 9 cm. in length and cleared it in 
creosote, when it was evident that sphincters were not present. 
The regenerated tail is of course not segmented and the scaling 
(irregular small scales) is quite irregular. A cartilaginous 
tube is present, the cartilage of which is calcified in the middle 
of the thickness of the rmg, not on its mner and outer edges as 
in the Gecko. The muscles are very numerous in transverse 
section (about fifty bands cut across), and these are separated 
from the cartilaginous tube not by fat bands but by dense 
conncctive tissue, which is continuous with the subcutaneous 
