M. E. Hesse on the Pranizze and Ancei. 413 
second pair of footjaws, also composed of four joints, of which 
the apical one is the narrowest ; these, which, like the preceding, 
are in a vertical position, close the buccal orifice. 
The head, in the transformation of the females into Ancei, is 
the last part to undergo metamorphosis; the author has seen 
individuals in which the whole body had become changed, whilst 
the head still retained its Praniza-form. 
The lower surface of the thorax is covered throughout with 
large oval laminz, which spring from the outer margin and join 
in the median line; these form a large incubatory pouch, in 
which the ova and young are contained. 
On the Habits of the Ancei. 
The fecundation of the females is effected while they are still 
in the Praniza-state. Immediately afterwards they become 
transformed into Ancez, and the ova make their appearance ; 
but, as in many other Crustacea, the young do not at once quit 
their mother, but remain attached beneath her thorax, probably 
waiting until she shall transport them into situations where 
they will be able to find their proper nourishment. In a few 
days, however, they disperse, swimming with great rapidity. 
After the exclusion of the young, the female appears quite 
empty and reduced almost to a mere ‘skin ; but through this the 
digestive apparatus, still containing some food, may be detected: 
in this condition their movements are very slow, and they soon 
perish. The existence of the males, on the contrary, may be 
much more prolonged: the author has kept one of them alive 
for two years, although it was placed in unfavourable cireum- 
stances. The Pranize, also, may live for a long time: some of 
them were kept for two years before undergoing their trans- 
formation into Ancei. Their vitality appears to be extraordinary. 
In examining them under the microscope, M. Hesse, in order to 
paralyze their movements, immersed them in fresh water, and 
even mixed this with alcohol, and kept them in this fluid until 
all motion, and even circulation, was suspended; but neverthe- 
less, by putting them again into sea-water, he found them alive 
and active on the following day. 
The reproduction of the Ance: appears to take place at all 
seasons, young animals of various ages being always found mixed 
with the adults. Nevertheless the author thinks that fecunda- 
tion takes place in September, October, and November. 
All the individuals found upon fishes were in the Praniza- 
form, and these speedily became transformed into Ancez ; those 
obtained on the shore, and mixed with Ancez, rarely underwent 
this metamorphosis. The Pranize inhabit the interior of the 
mouth of fishes, fixing themselves upon the palate and the 
