SEPIID^. 43 



The coloration of the eggs has not escaped the observation of 

 Aristotle, hut the explanation which he gives is more than 

 doubtful. The ver}^ opaque and very dark skin of the excluded 

 egg, later becomes thinner and nearly translucent. At the last 

 period of development, if the skin is torn away and the viteline 

 sack detached, one can introduce to the world, as I have often 

 done, the young Sepia. It swims immediately, and changes 

 color with the greatest facility. 



The coloration of the Sepias several centimetres in length is 

 more variable than that of the adults. The zebra-like black 

 bands are not seen, but the general tint changes instantly fi'om 

 gray to wine-brown, to violet, to green. The young Sepias sink 

 into the sand, only showing a part of the back and the head; 

 the}^ swim like the adults, but ascend an'd descend more fre- 

 quently. 



The eye of the Sepia has a very strange appearance ; the dark 

 pupil representing exactly a (o. It is furnished with an upper 

 lid, colored by chromatophores, and a narrower, whitish under 

 lid ; there is also a very distinct palpebral sinus. 



The sea-water destined for respiration enters the cephalic 

 extremity of the branchial sack, and leaves by the siphon. The 

 alternate movements of the openings of the sack and siphon can 

 be readily seen. 



The branchial sack in a number of adult Sepias was dilated 

 from seventy to seventy-two times a minute, but in the young, 

 about an inch long, the inspirations reached 140 in a minute. 

 This result surprised me ; it confirms, for animals of variable 

 temperature, the law established for those of fixed temperature, 

 that the number of inspirations is in inverse ratio to the age. 



The use of the tentacular arms of the Sepias was absolutel3^ 

 unknown to me until I had the satisfaction to see them in motion 

 on a morning of the month of August (186*1). A case of the 

 aquarium had contained for nearly a month a Sepia of medium 

 size, which, du.ring that time, had taken no nourishment. I threw 

 to it a rather large-sized fish (Caranx), which swam towards the 

 retreat of the Sepia — who had hardly perceived it, when, with 

 prodigious celerity and precision, he unrolled and launched for- 

 ward his tentacular arms, seized the fish and drew it towards his 

 mouth. The tentacular arms then retracted and disappeared, 

 but the sessile arms wrapped themselves 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 

 while ; 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 the muscles of the back. 



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



