CAUDAL AUTOTOMY AND REGENERATION IN THE GECKO 79 
dorsalmost halves which are separated by the vertebral neural 
spine, to form altogether six posterior muscle extremities. 
Each of the four ventral processes (Text-fig. 3, D) end pos- 
teriorly ina similar manner. ‘Thus on the posterior side of the 
segment there are altogether ten points of termination of the 
muscles instead of sixteen, since twelve of these fuse together 
in pairs and only those in the mid-dorsal and mid-ventral lines 
persist separately. Text-fig. 3, E, F illustrates respectively 
dorsal and lateral views of the musculature of several adjacent 
segments, from the latter of which it will be seen that the 
lateral posterior processes, which contract most vigorously in 
tail flexion or autotomy, become attached to the strong pro- 
TEXT-FIG. 3. 
Structure of the Original Tail of the Gecko and of the Tail of Calotes. 
A. Front end-on aspect of the piece of separated-off tail after 
autotomy (x cir.2). Eight large muscle processes are seen which 
were, before autotomy, lodged in the eight interseptal recesses 
seen in fig. B, B. Posterior end-on aspect of the stump of the tail 
after autotomy (x cir. 2). Eight recesses (situated under the 
subcutaneous fat layer) are visible, separated from each other 
by radiating septa of connective tissue: these lodged the eight 
muscle processes seen in fig. A. The transverse processes are 
visible, also the extreme hind end of the haemal process. C. Dorsal 
aspect of the flexor muscles of a single tail (autotomy) segment 
(x cir. 2). D. Ventral aspect of the posterior flexor muscles of 
a single tail segment (x cir. 2). E. Dorsal aspect of the arrange- 
ment of the flexor muscles ( x cir. 2). F. Lateral ditto. G. Attach- 
ment of the flexor muscles to the fat bands seen in longitudinal 
sections (x cir. 2). H. The segmented subcutaneous fat layer 
exposed after removal of the skin from three of the tail segments 
(xcir. 2). J. Transverse section through the posterior half of 
a tail segment showing the central septal attachments of the fat 
layer. The spaces between the (cut) fat layer and the fat bands 
are empty and form the eight recesses referred to in figs. A and B. 
In the anterior half of a tail segment the fat layer is attached all 
round to the outer surface of the flexor muscles. K. The fat layer 
of three segments cut through in the mid-dorsal line and spread 
out. Very few fat cells are present in the thin mid-ventral area 
(x cir. 3). Lines of cleavage are visible. L. Transverse section of 
the tail of Calotes (x cir. 3). The multiple subdivision of the 
peripheral muscles and the absence of a fat layer and fat bands 
are noteworthy. The large internally-situated muscles run 
longitudinally the whole length of the tail. M. Portion of dorsal 
skin of the tail of Calotes ( x cir. 2). N. Dorsal aspect of muscles 
of tail of Calotes after removal of skin ( x cir. 2). O. Lateral ditto. 
P. Sphincter on caudal artery of Gecko seen in longitudinal 
section (magnification unrecorded. but about 70 diameters). 
