14 MATHILDE M. LANGE 
in length (it was shorter) and in its position nearer to the buccal 
funnel. In the further course of development this arm would 
probably have replaced the lost one. This case would indicate 
that sepia does not always renew the lost part of its arms by 
direct regeneration, but in some cases resorts to compensatory 
regulation to replace the lost organ. 
2. A histological study of regeneration 
The course of regeneration which takes place after injury 
can easily be divided into three distinct stages, viz., the healing 
of the.wound, the degeneration of the tissues, and the renewal 
of the same. However, I wish to draw attention to the fact 
that these histological processes need not necessarily follow each 
other in the same order as here mentioned. 
a. Wound healing. It is not possible to detect many changes 
in the wound shortly after operation. The only obvious alter- 
ation consists in a contraction of the edges of the wound, by which 
they form a kind of raised rim around the same. The greater 
part of the wound with the exception of the axial nerve is in 
some degree protected by this rim. The histological examination 
showed that the raised rim was formed by the connective tissue 
of the dermis, in its endeavor to contract over the wound. How- 
ever, only the externally located muscles are covered by the con- 
nective tissue, while the center of the arm, comprising the axial 
nerve with its surrounding connective tissue layer and the inner 
muscles, remain unprotected. Figure 17, which shows a longi- 
tudinal section through the center of an arm one and one-half 
hours after operation, illustrates these conditions. Only the 
external portions of the wound are covered, and the axial nerve 
even protrudes beyond the surrounding tissues. The only 
alteration visible in the tissues immediately adjacent to the 
wound is a slight disintegration in the inner transverse muscle 
in the central mass of nerve fibers (neuropil) and in the ganglion 
layer. This subject will be considered below (pp. 22 and 27). The 
main brachial artery is closed. It is hard to tell whether this 
is a natural condition or one produced by fixing. The artery 
