8 MATHILDE M. LANGE 
surrounding tissues and its components are no longer visible, 
not even with the help of a magnifying glass. The hitherto 
unprotected portion of the wound has been covered by a sub- 
stance, the nature of which could only be ascertained by means 
of a histological examination. This examination disclosed the 
fact that this covering consisted of blood. I am not able to 
state the exact amount of time which expires between the oper- 
ation and the bleeding. However, I was able to detect blood 
only on such pieces which had been fixed five or six hours or more 
after operation. Pieces which had been preserved previous to 
that time showed no traces of blood. Here is a case where the 
section of blood-vessels is not immediately followed by bleeding, 
but where the bleeding takes place a considerable time after 
operation. 
This, I think, is a fact which deserves notice. At first I 
thought that the blood which might have covered the wound 
at an earlier stage could have been washed away or that the 
animal bled from four to five hours before the bleeding stopped. 
But both these cases seem rather improbable. In the first 
place, I could not detect any moisture on the filter-paper which 
I placed on the open wound directly after operation; secondly, 
the conditions in which the Octopoda live would be very harmful 
to them if they were subject to prolonged bleedings from wounds 
in the arm. Brock believes that to a certain degree some rela- 
tion between the oecology of the animal and the relatively great 
regenerative power of the arm exists. He wrote as follows: 
Ohne die sehr niitzliche Eigenschaft, die Arme schnell und voll- 
standig zu regenerieren, wiirden die Cephalopoden wohl schwerlich 
die Konkurrenz mit anderen Mitbewohnern auf dem Riff aufnehmen 
kénnen, trotz der unvergleichlich reichen Jagdgriinde, welche es ihnen 
bietet. Es ist nicht schwer zu begreifen, dass Wohnorte von der 
Natur eines Korallenriffes den Armen eines Cephalopoden geradezu 
verhiingnisvoll werden miissen. So kann es nicht ttberraschen, bei 
den Octopoden der Korallenriffe so haufig versttimmelten oder in 
verschiedenen Stadien der Regeneration begriffenen Armen zu _be- 
gegnen. Von langarmigen Arten ist es tiberhaupt nicht mdglich 
gewesen, ein Exemplar mit unverletztem Arm zu erhalten. 
