456 
THE OCEAN WORLD. 
by reaction produces a rapid and jerking movement. Sometimes the 
arms aid tbe movement; the eyes of the animal are then much 
dilated, and its colour a clear livid yellow, finely shaded with red, and 
covered with bright spots. 
It is a singular fact that the creature notably changes colour under 
any exertion, so that the animal at rest and in motion are two different 
beings. When walking under water the tube is directed behind, its 
arms are spread out, the head is raised, and the body slightly inclined 
forward ; its mantle is then of a pearly grey, and the spots take the 
tint of wine-lees. When at rest the shades disappear. 
The Pinnoctopus (Fig. 317), another genera of this family, have 
Fig. 317. Pinnoctopus corolliformis (D’Orbigoy). 
Fig. 318. Cirrotheutis Mulleri (Eschric& fc )' 
the body oblong, with lateral expansions, as represented in the 
companying figure. 
In Cirrotheutis the arms are completely united in their whole eS' 
tent by a thin membrane furnished with cirri, which alternate vvith 
certain suckers arranged in one row. Only one sjiecies of this gene) 3, 
is known as an inhabitant of northern seas, which is represented 
Fig. 318. 
It is no easy task to separate the real from the fabulous history 0 
the Cephalopods. Aristotle and Pliny have alike assisted, by their m al ' 
vellous relations, to throw that halo of wonder round it which the lig* 1 ® 
of modem science has not altogether dispelled. Pliny the ancie 11 
