42 SEPIID^. 



death is equally announced by a change of colors, which grow 

 dull. 



The swimming of the Sepia is differently effected, according 

 to the speed required. A moderate progression is equally easy 

 forwards or backwards. When the animal moves forward, the 

 body remains horizontal ; the tentacles, united and extended in 

 front, rest on the fourth pair of arms. The Sepia follows in this 

 manner the course of the water, the resistance of which bends 

 the extremities of the united arms. A moderate backward move- 

 ment is effected in the same manner ; but the tentacles are more' 

 elongated and their extremities are somewhat parted ; the arms 

 are raised to the line of the body. The undulations of the fins 

 commence at the front or rear, according to the direction which 

 the animal takes. This method of swimming, due entirely to the 

 fins, is not slow, for the normal movement of the Sepia is easy, 

 elegant and rapid ; but an occasion of disquietude, as the sight 

 of an enemy, or a noise, causes a much accelerated, jerky and 

 retrograde movement. To effect this the animal spreads its arms 

 and suddenly reunites them ; whilst the fins, reduced to inaction, 

 are folded upon the ventral face of the body, the posterior 

 extremity of one of them covering that of the other. 



This accelerated action is then due to the movements of the 

 arms, which cause a series of extremely rapid progressions, in 

 which, perhaps, the funnel assists by its discharges. It is erro- 

 neous to regard the funnel, as some have done, as the principal 

 or onl}^ swimming organ of the cephalopods. 



The deposition of the eggs occurs some days after fecunda- 

 tion. I have been a witness to the deposition of three or four 

 eggs, but I was not able to distinguish the method of the opera- 

 tion. A female laid about one hundred eggs, about fifty in a 

 corner of the aquarium, and fifty on the opposite side. These 

 eggs were enrolled by their peduncles around the long leaves of 

 Zostera marina (xviii, 13, 14). The larger part of the eggs were 

 laid in the night, for I remarked them in the morning for the first 

 time ; they were already black. 



When the Sepia is laying, she embraces the leaf of Zostera 

 with her tentacles, and a few instants afterwards the egg is 

 attached. The female removed herself but little from her eggs, 

 but she appeared to me to be sick, exhausted ; she died three 

 daj'^s after having commenced oviposition, and only a few hours 

 after having attached her last eggs. 



I found the ovary filled with a considerable quantity of eggs 

 in all stages of development ; the most advanced were already 

 furnished with a white and opaque covering, but none of them 

 were black like those attached to the Zosteras. The black color, 

 then, is acquired at the moment of deposition, and it is probably 

 due to a secretion of the glands which surround the oviduct. 



