IIAHITS OF THE CEPHALOPODA. ()3 



The nutation ol'tlie Toiilpe does not at all resemble that of the 

 otlier cephalopods. To swim, the Poulpe raises its sack above 

 the arms, fills it witli water, and, at the moment tliat the water 

 leaves the funnel, suddenly closes its arms — wliich are furnished 

 wiili a swininiini>- wel) at tlieir base. The movement ol" the 

 animal is thus very ol)li(iue, and it is nlso heavy and cliunsy, as 

 Iteinu;- unused to that mode of locomotion.* 



Sepia officinaUa. — Tiie useof tlie tentacular arms of the Sei)ias 

 was absolutely unknown to me until I had the satisfaction to see 

 them in motion on a morning of Ihe month of August (18(3t). 

 A case of the aquarium had contained for nearly a month a Sepia 

 of medium size, which, during that time, had taken no nonrish- 

 ment. 1 threw to it a rather large-sized fish {Caranx)^ which 

 swam towards tlie retreat of the l^lepia — who had hardly per- 

 ceived it, when, with prodigious celerity and i)recision, he un- 

 rolled and launched forward his tentacular arms, seized the tish 

 and drew it towards his mouth. The tentacular arms then 

 retracted and disappeared, but the sessile arms wrapped them- 

 selves closely around the head and anterior portion of the body 

 of the unfortunate fish — which never made a movement after it 

 was caught. The Sepia swam about easily in all directions for 

 about an hour, eating the Avhile ; it then let the remains of the 

 fish drop to the bottom of the aquarium, having opened the skull 

 and devoured the brain as well as a portion of tlie muscles of 

 the back. 



The use of the tentacular arms is then no longer doubtful ; 

 they serve for the seizure of food. I have been able to verify 

 this fact a second time in examining the Calamaries — which pur- 

 sued a troupe of little fishes, capturing them with these members. 

 Moderate forw^ard or backward progression is not due solely- to 

 the fins as I have previously stated, but is assisted by the ex- 

 l)ulsion of w'ater from the funnel ; if the animal move forward, 

 the funnel is recurved in front, and forms nearly a right-angle 

 with the body ; in retrograde movement the siphon becomes 

 horizontal ; it is placed to the right or left wdien the Se})ia 

 would turn, and is strongly recurved from front to l)ack when it 

 would mount to the surlace of the water. 



* Dr. Paul Fischer, Ann. des Sc. Nat., 5 ser., vi, 308^320, 1866. 



