184: ANCEIDA. 
In the earlier period of its parasitic life, the female 
takes a green colour, which at a later stage deepens into 
a bright blue. We speak of the common species round 
our coast, to which Montagu gave the specific name of 
ceruleata. M. Hesse has figured one of a brilliant red ; 
we have never seen such, but it is not improbable that 
some species may change in their colour, which most pro- 
bably varies with the condition of the food, for we have 
taken them white, grey, green, blue, and brown. 
An examination of the material confined within this 
portion of the pereion shows it to consist of oil and fat 
globules, and we have been able to determine that it is 
intimately associated with the nourishment of the animal, 
since by keeping them without food the coloured mass 
decreases in size. It is such an animal that Mr. Spence 
Bate figured in his paper ‘fon Praniza and Anceus,” 
** Annals Nat. Hist.” for Sept. 1858, where he observes, 
** After a few days the blue mass, which first appeared to 
fill and distend the large segment of the pereion, gra- 
dually diminished, apparently deteriorating. It recedes 
first from the margin; in so doing it displays a series 
of layers, placed one before the other, lying across the 
animal, There were indications of these layers being 
divided by cross sections. The relation that this co- 
loured mass holds to that of the ova which, at a later 
period, take its place, we know not; but we are inclined 
to believe that it is a reservoir of fat on which the animal 
is supported during the period of incubation. 
We have not been fortunate enough to obtain em- 
bryonic forms of the larve so young as those figured by 
M. Hesse (plate 1, figs. 5, 6, and 7), which, by their 
single central eye and general form, resemble the larve 
of some entomostracous species of crustacea, a form 
that Dr. Fritz Miiller contends, with some apparent show 
