AUACHNIDES. 
501 
TRIBE II.-CERATOPHTHALMA. 
\ 
With a shell, and the eyes seated on peduncles.—Its genera 
are, 3. Branchipus ; and, 4. Artemia. 
ORDER VIII.—XYPHOSURA. 
Body subdivided, without a syphon; base of the feet, except 
the last two, spiny, and acting as jaws ; shell covering the whole 
body, hard, in two compartments, longitudinally furrowed above; 
body terminated by a hard sabre-shaped process. 
It has but one genus ; 1. Limulus. 
ORDER IX.—SIPHONOSTOMA. 
With a syphon or proboscis, but is sometimes invisible, and 
provided with palpi for suction ; with more than six or seven 
pairs of feet; shell of one piece, soft, membranous, and not en¬ 
tirely covering the body. . 
TRIBE I.-CALIGIDES. 
Shell distinct, with the body more or less oval.—It consists 
of four genera: 1. Argulus ; 2. Caligus ; 3. Anthosoma; 4. 
Cecrops. 
TRIBE II.-LERNiEIFORMES. 
Destitute of a shell; body nearly cylindrical, jointed, and 
having the appearance of a worm. — It consists but of one ge¬ 
nus ; 1. Dichelesthium. 
CLASS VII.—ARACHNIDES. 
The animals are oviparous and have articulated members, and 
do not undergo any metamorphosis ; they respire by a trachaea, 
or by means of branchiae ; the apertures for the admission of 
air is stigmatiform, and having no antennae. 
