452 



DR. W. E. HOYLE ON CEPHALOPODS 



[May 7, 



across without any transverse ridges in it. The groove which 

 runs along the arm is very wide and well-marked ; 5 cm. from 

 the tip it measures 2 mm. across when opened out ; it is crossed 

 by a series of narrow close-set ridges, of which there are about 

 three to a millimetre. 



In several specimens the arms have been lost and show different 

 stages in the process of repair. In 161 the second right arm had 

 been removed just above the umbrella margin, and its present 

 condition is shown in PL XX. fig. 1. The two suckers project far 

 above the cut end of the arm, and appear to have been drawn 

 over by the contraction of tissues consequent on the healing 

 process. The cross section of the arm is now much less than that 

 of a normal arm at the same level. Just within the integument 

 is a small fleshy, curved process (r), the rudiment which will grow 

 into the new arm. Further stages maj^ be seen in 157, where no 

 less than four arms have been amputated and are in different 

 stages of regeneration. In the fourth left arm (PI. XX. fig. 2) 

 the rudiment is 8 mm. in length and bears about thirty suckers ; 

 the exact number is impossible to ascertain, those towaixls the tip 

 being very minute. In the third right arm (PI. XX. fig. 3) the 

 length of the restored "portion is 1 5 mm., but the number of suckers 

 has not much increased, being only about thirty-eight ; their size 

 is, however, much greater. The chief point of interest about 

 these specimens is that in every case the rudiment of the new 

 arm arises in the same ]30sition, namely just within the integu- 

 ment of the outer aspect of the arm. 



Text-fiff. 129. 



Radula of Folypus horsti ; X 65. 



As the radula of this species has not 3'et been figured, I give a 

 drawing of it in text-fig. 129. 



Polypus horsti is very commonly used for food in Zanzibar, and 



