322 TUNICATA.—SALPADZ. 
motion resembling that of a serpent—the chain 
often extending to many feet in length —it 1s 
evident that this motion must arise from the un- 
equal manner in which the different individuals 
act throughout the whole line... . 
‘“‘T had occasion to remark of this animal, that, 
like the MWeduse and analogous tribes, 1t cannot 
bear to be confined in a limited portion of water, 
as it died, even in the ship’s bucket, in less than 
half an hour—a very remarkable circumstance in 
the economy of these imperfect animals. 
“Hitherto, this genus is only known as the 
inhabitant of hot climates, and of the Mediterra- 
nean Sea. I found it in great abundance in the | 
harbours of Canna and Campbelltown, rising to the 
surface in calm weather, and crowding the water 
as the Meduse often do at the same time of the 
fremr ss, Se: 
“JT was desirous of observing whether this 
animal, like many other of the marine worms, 
emitted light, but had no opportunity of ascertain- 
ing the fact, as they seemed always to retire to the 
bottom at sunset, and those which were taken on 
board died (as I have already observed), in a very 
short time.” * 
The Pyrosomata are aggregated in another man- 
ner. ‘They consist of lengthened individual Asci- 
dians, united to each other at their basal part, and 
free at the opposite extremity, with their connexion 
so arranged as to compose numerous and regular 
rings, which concur to form a long, free cylinder, 
or tube, open at one extremity and closed at the 
other. 
Cuvier states, that this great cylinder swims 
* Western Isles, ii. 187. 
