the Mouth in Sucking Crustacea. 9 
occurs not unfrequently in the Sound and along the north 
coast of Zealand. It was already known to Slabber, and was 
described some years ago by Van Beneden (“ Rech. sur les 
Crustacés de Heleigne,? Mém. d. Acad. Belge, xxxii. p. 88, 
t. 15) as Slabberina agata, but is doubtless the same species 
that Leach described as Hurydice pulchra. Van Beneden re- 
fers it to Idothee. 
_ The mandibles are destitute of grinders; but their prehen- 
sile part is, on the contrary, extraordinarily large, shaped like a 
flat cup, the outline being almost quadrangular, the outer 
corner pointed, the whole inner edge finely sharpened, hard as 
glass, undulato-dentate, the inner corner drawn out into a 
8 dagger-like peg. The inner lobe is fixed closely under 
the outer lobe, large, membranaceous, divided into two lobules, 
of which the foremost is entire and covered with sete in Ciro- 
lana, but digitilobate in Hurydice; whilst the posterior lobule 
in both genera is cultelliform, with a close row of pointed thorns 
along the inner margin, which gives to the lobule the appearance 
of a tenon-saw. The stem of the mandible is long, the palpus 
slender, and, when not used, placed in a groove round the large 
labrum and the small clypeus, with the last joint slung round 
the root of the posterior antenna. ‘The first pair of maxille 
possess two lobes coalescing with the stem; the inner lobe is 
much abbreviated and has three cylindrical slender append- 
ages, which in Cirolana are ied ude apinubins towards the 
- apex, and furnished with a hard thorn-shaped terminal joint, 
but which in Hurydice are soft, pointed, and hairy; the outer 
lobe is also rather short, particularly in Cirolana, somewhat 
arched inwards (fig. 3,x), powerful, the apex armed with a 
bundle of long, exceedingly hard, and pointed thorns, groups 
of similar thorns occurring all along the inner margin, which, 
in Ewrydice, are much elongated and in part spinulous on the 
inner side. ‘The second pair of maxille (fig. 3,*) are small, 
their inner lobe very short, with feather-like sete and hairy 
‘membranaceous digitiform appendages; the middle lobe and 
ok are represented by a pair of uniform pointed leaflets. 
he maxillipeds (fig. 3, px) have oval hinges, small stem, 
rudimentary lobes, and fully developed, slender, flat palpus. 
The forehead and clypeus are, in Cvrolana, trapezoid, flat, in 
Eurydice vaulted, the frontal cone protruding between the first 
pair of antenne (fig. 3.a,f). 
Cirolane represent, no doubt, the highest development of 
the Crustacean type amongst Isopoda. The outer lobes of 
their mandibles are built exactly on the same plan as the car- 
nassial teeth of mammalia. They are furnished with pegs to 
be driven into the body of the victim, one from either side, 
