ON ACEPHALA. 415 
composed of small whitish lumps, visible through the parietes 
of the vessels, sometimes of a reddish brown, and transparent. 
These observations may be still more assisted, by holding the 
animal vertically, with the nucleus downwards; then, as the 
blood pushed into the aorta, is forced to ascend against its 
own Weight, its march is much less rapid, and the movement 
of the globules can be very well followed. 
These animals are essentially marine, and are seldom found, 
except in the high sea. It appears that they exist in all the 
seas of warm climates, and even in the Mediterranean, on the 
African coast. Farther northward they do not seem to be 
found, or if so, they have been driven thither by currents or 
tempests. They are sometimes found in great abundance in 
the deep water, at a great distance from the shore, either 
solitary, or united according to a particular method for each 
Species, so as to form long cords or ribands, which float in a 
serpentine manner at no great distance from the surface. It 
is especially during the night that they are most perceptible, 
in consequence of the phosphoric property with which they 
are endowed to so high a degree. All navigators are agreed 
upon this subject, and say that the salpze, when chained 
together, produce the effect of long ribands of fire, drawn 
along by the currents. 
Although they really possess the locomotive faculty, it is 
extremely probable that they are the sport of the waves and 
winds, which drive them along in their own direction. ‘This 
appears most likely with regard to the individuals which are 
linked together. 
Their nutriment, without doubt, is entirely animal, and 
composed of animalcule, and even of the amorphous matter 
which is found in such great abundance in the sea-water, 
which traversing the cavity of their mantle, serves at once for 
locomotion, nutrition, and respiration. The salpz are true 
hermaphrodites. . 
