459 
Mr Brindley , Regeneration in Samia ailanthus. 
instances of homoeosis, there is among Arthropod animals a high 
degree of constancy of form and feature in the regeneration after 
particular injuries; i.e., if regeneration occurs at all, the new limb, 
though at least at first of small size, is well-formed and ap- 
parently an efficient organ, and in some cases it is known that 
the mechanism of regeneration is so specialised that neither the 
stage at which injury was inflicted or the degree of injury, so far 
as it is possible to gauge the latter accurately, make no profound 
difference to the form assumed by the regenerated limb. The 
above statements however appear to receive but partial support 
from those insects in which the post-embryonic development 
includes complete pupation, though the number of experiments 
hitherto made is very small and these have been confined to the 
Lepidoptera. Newport amputated the 3-jointed larval leg in its 
basal or second joint just before pupation and described the results 
for about 15 cases. In the imagos there was much variation in 
the condition of the injured limbs. In all cases femur, tibia, and 
tarsus could be distinguished, but the number of tarsal joints varied 
considerably. In all, however, the terminal claw of the tarsus was 
present. This fact and the drawings which illustrate his paper 
suggest that the reproduced tarsus in all these cases should be 
regarded as representing the whole of the normal tarsus, rather 
than for instance that a 3-jointed tarsus should be considered as 
equivalent to three particular joints of the normal tarsus. How- 
ever this matter be regarded, it remains that the tarsus is 
sufficiently represented to bear the normal termination, the claw: 
so that his observations illustrate the tendency, seen so widely in 
the regenerated limbs of Arthropods, to produce the proper 
terminal structures, though normality in the number of joints 
may be absent. Chapman has extended the range of the enquiry 
by amputation of the larval leg in the penultimate instar before 
pupation, and secured uniformity of method by always amputating 
the basal joint and performing the operation immediately after an 
ecdysis. In the imago the claw apparatus is present in the six or 
seven cases this author describes and figures, though there is 
considerable variation in the number of joints, and in one instance 
the imaginal limb is only two rounded joints bearing a dwarf claw. 
Dr Chapman informs me that he has made several hundred muti- 
lations in different instars with the view of observing the progress 
made from stadium to stadium, and it is to be hoped that the 
results of these, the first at all extensive experiments, will be 
published by him, as to my great regret I have so far had no 
opportunity of taking advantage of his very kind suggestion that 
I should examine his material myself. 
The following observations were made while I was unaware 
that Dr Chapman was examining the same subject, and were 
