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CRUSTACEANS. 
Euphausiidce, are hatched in the Nauplius stage. Most Schizopods are small, but 
species belonging to the genera Lophogaster and Gnathophausia measuring as 
much as 6 inches in length have been obtained. To the family Mysiclce belongs 
the genus My sis, or opossum-shrimps, among which is M. veheta from certain lakes 
in Northern Europe. Into these lakes the species is presumed to have entered 
while they were connected with the sea; a supposition borne out by the fact that 
it is nearly related to M. oculata, now living in the Arctic Ocean. 
The Mantis-Shrimps,— Order Stomatopoda. 
The mantis-shrimps ( Squillidce ), which owe their name to the resemblance 
that their seizing limbs bear to those of the insect mantis, are abundant in tropical 
seas, where they sometimes reach a large size. 
Although bearing a general likeness to the long- 
tailed Decapods, they may be recognised by 
certain prominent characters. A glance at the 
accompanying figure will show that the carapace 
is so short as to leave the hinder segments of 
the thorax uncovered, and, since the gills are 
attached to the abdominal limbs, it forms no 
branchial chamber. Only three pairs of limbs 
are modified into jaws, these being the mandibles 
and two pairs of maxillae. The remaining eight 
pairs of thoracic limbs are foot-like, the large 
prehensorial pair corresponding to the second 
maxillipedes of a Decapod. Two kinds of 
mantis-shrimp are occasionally met with in the 
English Channel, namely, Squilla desmaresti 
and S. 'mantis. The former is not uncommon 
along the shallower parts of the shores of 
Jersey, but as it lives in deep burrows among 
the roots of sea-grass, in a zone never uncovered 
by the tide, its appearance is infrequent. The 
allied North American Lysiosquilla excavatrix 
is found in the sand below low-water-mark, 
where it is protected from the full force of the 
ocean swell, and inhabits deep cylindrical 
burrows which are nearly vertical and go down 
mantis-shrimp (reduced). for several feet. 
Sessile-Eyed Series,— Edriopthalmata. 
We now come to the second great series of the Malacostraca, in which the 
compound eyes are generally sessile, and never mounted on movable stalks. As a 
rule, the last seven segments of the thorax are not covered by the carapace, and 
the last four are always free. The first order, Cumacea, is in many respects inter- 
