ae MATHILDE M. LANGE 
after a period of several hours (five to six). The wound is then 
completely overspread with blood which serves as a preliminary 
covering for the same. After bleeding, the protrusion of the 
axial nerve disappears. The last two suckers at the obtuse end 
of the arm are abnormally drawn up, as if they also participated 
in the preliminary closing of the wound. ‘The final wound healing 
by epithelium occurs in some animals within the first twenty- 
four hours after operation; in most cases, however, it takes from 
thirty-six to forty-eight hours. 
2. Change of form. The distal suckers which were drawn up 
regain their normal position. The first visible sign of regener- 
ation appears in the shape of a little knob near the external side 
of the arm. The knob develops into a little lash-like appendage, 
which appears like a thin rod in comparison to the arm stump. 
3. Formation of the suckers. The newly formed suckers must 
be divided into two groups, those that are formed as suckers of 
the regenerated piece proper and those formed at the obtuse 
end of the arm stump. All suckers first appear in the form. 
of little transverse folds. Later on they are rounded off to 
little papillae. The newly formed suckers at the obtuse end 
of the arm are arranged in single file. They remain in a single 
row during the greater part of their development. On the other 
hand, the suckers of the regenerated piece exhibit the final 
double-rowed arrangement at a very early stage of their develop- 
ment. The sucker cavity and the adhesive part are both formed 
by invagination. At the base of the regenerated piece, one or 
two suckers (sometimes three) always remain in single file. 
4. The chromatophores. The first new chromatophores appear 
about three to four weeks after operation. They are smaller 
and of a lighter shade than the normal chromatophores. 
The histological study led to the following results: 
1. Wound healing. The wound is at first unprotected (five 
to six hours). Then a preliminary covering, consisting chiefly 
of a clot of agglutinated blood-corpuscles, is formed. From 
this blood-clot a primary blastema is gradually evolved, the 
blood-plasm becoming less and less, and the agglutinated blood- 
corpuscles forming a fine network. The epithelium remains 
