Dr. F. Miiller on the Metamorphoses of the Prawns. 107 
freely over two or three of the newly formed segments. Anteriorly 
it is at first covered by the contiguous eyes (fig. 3) ; when these 
subsequently separate, it covers the interspace and the base of 
the ocular peduncles with a triangular process which runs out 
into a spine reaching a length of 0°12 mill. (fig. 6). The cara- 
pace has no other spiniform processes. 
Beneath this anterior part of the carapace and the paired eyes 
is situated the single eye ; the entire space between the origins 
of the anterior antenne (01 mill.) is oceupied by two large 
ganglia which meet in the median line; their anterior surfaces 
are strongly convex, and over both of them the integument is 
extended in a nearly semicircular form. From the depths of 
the free space thus left between the ganglia and the skin a 
clavate bacillus (“ crystalline cone”) rises until it nearly reaches 
the skin; at its lower part it is surrounded by black pigment- 
granules. The skin appears to me in this species to be destitute 
of lentiform thickenings. 
The antenne still form the chief instruments of locomotion ; 
whilst in all other Zoée (of the Stomapoda, Crabs, Porcellane, 
Pagurt, and the Prawns which quit the egg in the Zoéa-form) 
they have nothing to do with locomotion. 
The anterior (inner) antenne (0-4 mill. in length) now appear 
to be divided into four joints, the first of which occupies nearly 
half the length ; the longest of the three strong apical bristles 
is nearly twice as long as the antenna. Close to the apical 
bristles and outside of them, stand one or two delicate bacilli, 
0-09 mill. in length; there are one or two more of these a little 
below the apex on the outside of the terminal joint. The pos- 
terior (outer) antenne are now close beside the inner ones, and 
attain only about two-thirds of their length; their thick stem 
shows two, their inner (anterior) branch three, and their outer 
(posterior) branch as many as ten joints. As before, the inner 
branch is but little shorter, although much weaker, than the 
outer one. The outer branch has as many as ten plumose 
bristles, of which four stand at the apex and the others at the 
ends of the six preceding joints. 
The large upper lip (fie: 41) is very much in the form of the 
helmet of a Prussian soldier, which has only to be imagined rather 
broader and with its peak considerably enlarged and emarginated 
in the middle. The helmet, of which the point is directed for- 
wards, is immoveable, and from it muscles pass to the moveable 
peak which covers the mouth and a part of the upper jaws. 
In the examination of the uninjured animal from below, the 
only part of the powerful upper jaws (fig. 4 111) that is seen is a 
long tooth with two or three points, which projects far beyond 
the more deeply seated masticatory surface, which is beset with 
