SEPTID®. 41 
The chalky thickening of the shell is used as a dentifrice,* and 
also for modeling metallic objects, its surface receiving an 
exceedingly accurate impression. Cuttle-bone is a favorite beak- 
sharpener for caged birds. 
The following observations on Sepia officinalis were made by 
Dr. Paul Fischer, in August, 1866, at the aquarium of Arcachon, 
Gironde, France. Besides the usual glass cases, there are here 
vast basins with earth bottoms, and of moderate depth, which 
receive the results of the fishery on the shore itself. Without 
this commodious arrangement, it would be impossible to preserve 
living, the very delicate animals. 
The fishermen gather the young individuals called Casserons, 
for food. When caught for the aquarium, they are at first placed 
in the great basins ; they show themselves very timid, discharge 
inky clouds, and hide under floating objects ; always shaded, they 
remain immobile in the horizontal position, nearly touching the 
earth by their ventral surface. After some days of repose, they 
are transferred to a glass aquarium. 
The normal position of the Sepia is horizontal, the fins undu- 
lating gently, the sessile arms joined at their extremities, forming 
a sort of pyramid or tetrahedon. In this position the appearance 
of the head and arms is very like that of an elephant’s head with 
the trunk. The tentacular arms remain contracted within the 
others when in repose; a position difficult to understand, as after 
death they are found to be more than double the length of the 
sessile arms. Sometimes the first pair of arms are raised into a 
vertical position, like antennz, the others preserving their normal 
attitude ; sometimes, also, the fourth pair of arms drop towards 
the earth for a few moments, and much elongate themselves. 
The coloring of the Sepia is eminently variable ; but if the day 
is clear, the dorsal surface and arms are magnificently striped ; 
the edges of the fins are black, and their superior face is orna- 
mented with spots of the same color. On the back of large indi- 
viduals is seen two large obscure spots, which vary in intensity 
and sometimes entirely disappear. The eye is fatigued in fol- 
lowing the incessant variation of coloring caused by the constant 
movement of the pigment cells, and the metallic reflections of 
the head and arms are glorious beyond human skill to reproduce. 
The skin is usually smooth; but when the animal becomes irri- 
tated, it shows granulations, principally on the head and back. 
This is accompanied by a retraction of the arms, which appear 
both shorter and narrower; the extremities no longer touch, but 
curve slightly. At the same time the colors change, a uniform 
gray tint takes the place of the striped bands. The approach of 

* This manufacture is extensively pursued at Liverpool ; as much as 12 
ewt. of cuttle-bone arriving at one time for this parpose. 
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