70 W. N. F. WOODLAND 
When a Gecko is wounded on the tail, it usually subsequently 
sheds the tail immediately anterior to the wound as the 
easiest method of repairing the injury.’ 
(4) The regenerated tail, not being segmented in character 
(see description of structure below), cannot be shed in parts 
(its thin fragile extremity can, however, be easily broken or 
bitten off), though it may be shed as a whole either at its 
Junction with the stump of the original tail or attached to 
a few segments of the original tail. This has been proved by 
numerous experiments which I need not record. Usually (in 
eleven out of thirteen experiments) when a Gecko is caught by 
the thick anterior portion of the regenerated tail, the whole of 
the regenerated tail is shed at its junction with the stump of the 
original tail ; in some cases, however (in two out of the thirteen 
experiments), the regenerated tail is shed with either one or two 
(rarely more) of the posterior segments of the original tail 
attached ; im other words, autotomy at the junction of the 
regenerated with the original tail is only a little more easy than 
autotomy at any ordinary joint of the original tail. 
(5) Whenever autotomy occurs, the escape of blood from 
the caudal artery is practically nil. If, however, a segment 
be cut through in the middle, haemorrhage is a little more 
pronounced, and if the base of the tail be cut through (i.e. 
anterior to the first jomt or autotomy plane) bleeding is profuse. 
The explanation of these facts will be found in the description 
of the structure of the original tail given below. 
NAKED-EYE OBSERVATIONS ON NoRMAL CAUDAL 
REGENERATION. 
(6) Regeneration of a tail only normally occurs at the 
posterior surface (a) of the unsegmented base of the original 
tail, or (b) of a segment of the original tail, or (c) of the end of 
the regenerated tail which has had a portion broken off (not 
autotomized). ‘Text-fig. 1, F-Q, shows the stages of develop- 
* In these cases, apparently, the weakening of the joint caused by the 
wound renders seizure of the tail posteriorly unnecessary. 
