272 M.E. Hesse on the Means by which certain Species of 
ceivable that, if the prevision which presides over the conserva- 
tion of all existences did not come to the aid of these degraded 
Crustaceans, they would speedily disappear, or, at least, that an 
entire family would perish with the fish which served it at once as 
a prey and a place of shelter. It is, therefore, of great import- 
ance to prevent such a result. I propose to see whether the 
facts which I have ascertained may justly be regarded as des- 
tined to provide against this destruction. 
It is not rare to find female Trebie, Caligi, Pandore, and 
Chondracanthi to which young Crustacea of the same species 
are affixed by a cord, which, although it cannot be called wmbi- 
lical, may be denominated, by analogy, the frontal cord. This 
bond which unites the embryo with its mother does not fulfil 
functions analogous to those of the umbilical cord in the higher 
animals, but is destined simply to unite the one to the other. 
Attached by one of its extremities to the anterior part of the 
frontal margin of the young Crustacean, it is affixed by the 
other end to the body of the mother, by means of a circular 
dilatation in the form of a sucker; and it is sufficiently long 
and flexible to allow the young Crustacean to act to a certain 
extent independently of its mother, without disturbing her 
movements, and to apply itself to tlie fish upon which they live 
in common. 
It is a spectacle at once surprising and interesting to see 
these embryos (especially those attached to the Trebie and Ca- 
ligi, which swim with tolerable rapidity) following the evolutions 
of their mother like a little boat towed along by. a larger vessel, 
or, again, as a fish attached to a line which “keeps it a prisoner, 
yields to the traction which is thus exerted upon it. 
What is the purpose of this curious union? Is it possible to 
assume it to be the effect of chance, when analogous facts are 
frequently presented, and have been ‘proved to occur, in several 
species of these Crustacea? Can it be supposed that it is for 
the purpose of the alimentation of the embryo by the mother, 
when the bond of union does not establish any internal relation 
between them, and they each obtain their own nourishment? 
I think not ; and we must therefore assume that there is some 
other motive. 
If we assume that this young Crustacean is a male, and that 
the female, seizing a favourable opportunity, passes, carrying 
it with her, from the fish on which they were living together, to 
another, we shall at once perceive the consequences of this 
transmigration, which, uniting in itself all the elements neces- 
sary for” reproduction, allows “this female and the male which 
accompanies her to found a new colony. This supposition does 
not appear to me improbable; for, of two things, one must be 
; 
