M.E. Hesse on the Pranizze and Ancei. _ 411 
resemble the curved scissors used by surgeons. These organs 
resemble the mandibles of insects, and appear to perform the 
same functions. The head, which is of a quadrilateral form, is 
divided into four equal parts by depressed lines which cut each 
other at right angles; the forehead is armed with three teeth, of 
which the middle one is generally small, acute or denticulated, 
and the lateral ones truncated at the apex and placed within 
the bases of the mandibles. In some species the middle tooth 
is notched in the centre, and its points are obtuse. 
The eyes are smaller and much less prominent than those of 
the Pranize ; they are composed of round facets, and placed at 
the base of the antenne. 
Seen from beneath, the head is entirely occupied by the buccal 
apparatus, which is completely covered by the two footjaws of 
the first pair; these are lamellar, triangular, slightly convex, 
denticulated, and ciliated on the rounded interior margin. 
These two plates, which present a small notch at the apex, in 
which is inserted a small, oval, ciliated, palpiform appendage, 
lie over each other in the middle, leaving a considerable free 
space at their base and apex; they are attached at their base 
by a hinge, upon which they turn so as to open downwards ; 
they are enclosed laterally by the projecting frame of the buccal 
apparatus. The footjaws of the second pair consist of three or 
four flat joints, diminishing in size from the base to the apex; they 
are destitute of both palpus and flagellum, and vary according to 
the species. Within these parts there is an apparatus the nature 
of which the author has been unable to ascertain with certainty : 
at the highest part, im the median line, is a round orifice, which 
may be asucker; below this is a sort of crescent-shaped aperture, 
then another round orifice accompanied by small acute jaws, and 
lastly a vertical aperture margined with a sort of lip. These 
parts are very difficult of detection. 
To the base of the buccal apparatus are attached three ciliated 
lamellar appendages, the median one triangular and covering 
the two others, which are rounded in form. These three lamine, 
which have some relation with the lamellar footjaws of the Epi- 
carides, have for their function to convey to the mouth, with the 
water which they set in motion by their constant agitation, the 
small objects which serve as the nutriment of these Crustacea ; 
these pass through the interval at the base of the first pair of 
footjaws. 
In the Ancez the first two thoracic segments become intimately 
united with the head ; the first two pairs of feet accompany them, 
and the cephalothoracic portion thus formed is separated by a 
considerable constriction from the three narrower thoracic seg- 
ments which follow, each of which bears a pair of legs. 
