ORDER NUDA. Ley 
long time, just as they were in the ovary, and thus swimming 
in long chains where the individuals are disposed in different 
ways, but each species always according to the same order. 
M. de Chamisso assures us that he has verified a still more 
singular fact relative to these animals ; it is, that the indivi- 
duals which have thus issued from a multiplex ovary are not 
furnished with a similar one, but produce isolated young 
ones of various forms, which have an ovary like that which 
produced their parent, so that there is alternately a genera- 
tion of a few isolated individuals, and another of numerous 
and aggregate ones, and that these two alternating genera- 
tions do not resemble each other. 
It is very certain that in some species little individuals 
have been observed adhering to the interior of large ones by 
a peculiar kind of sucker, which were different in form from 
those that contained them. 
_ These animals are very abundant in the Mediterranean and 
the warmer portions of the ocean, and are frequently phos- 
phorescent. 
The THALIAZ, Brown, have a small crest or vertical fin 
near the posterior extremity of the back. (Holothuria thalia, 
Gm., &c.) 
Of the SALP#, properly so called, some have a gelatinous 
dark-coloured plate in the substance of the mantle, and above 
the visceral mass, which may be the vestige of a shell. (Salpa 
scutigera, Cuy., &c.) 
In others it is a simple prominence of the same nature as 
the rest of the mantle, but thicker. (Salpa Tilesii, Cuv., &c.) 
Others, again, have neither plate nor prominence, but their 
mantle is extended by points, and of them 
Some have a point at each extremity. (Salpa maazima, 
Forsk., &c.) Others have two at the extremity nearest the 
mouth. (Salpa democratica, Forsk., &c.) ; and even three, or 
more, as Salpa tricuspis Id. . 
