CERAPUS. CRUSTACEA. 173 



L. ventricosa, Desm. (Squilla ventricosa, Muller.) Desm. Crust. 

 M(\. 



ORDER IV. AMPHIPODA. 



Head separate from the segment bearing the second feet-jaws 

 or anterior feet ; post-abdomen furnished with branchial and 

 swimming appendages below, narrow, elongated, and either 

 multiarticulate, striated transversely, or branched ; mandibles 

 with palpi ; vesicular bodies in the greater number at the 

 base of certain feet. 



FAMILY I. GAMMARIN.E. 



Posterior extremity of the body furnished with cylindrical or 

 conical appendages in the form of stylets, or without appen- 

 dages. 



Gen. 1. CERAPUS, Say. 



Antennae hairy ; feet of the first pair small and terminated by 

 a simple short claw ; the second pair very large, with a large 

 flattened, triangular hand, and a biarticulated thumb; the 

 three following pairs monodactyle, and the last four feet long, 

 slender, and directed backwards and upwards ; body linear, 

 of twelve segments, the last flattened and oval, and bifurcat- 

 ed at the extremity ; head with a small rostrum ; eyes pro- 

 jecting. 



C. tubularis, Say. About six lines long, and inhabiting a small cy- 

 lindrical tube, with the head, antennae, and first pair of feet pro- 

 jecting. Coasts of the United States. Desm. Crust. 271 



Gen. 2. LEUCOTHOE, Leach. Cancer, Mont. 

 Anterior pair of legs didactyle, the thumb biarticulate ; second 

 pair with a dilated and compressed hand, and a crooked 

 thumb ; extremity of the abdomen bent downwards. 



L. articulosa, Leach. (C. articulosus, Mont.) Inhabits British seas, 

 but is very rare. Mont. Lin. Trans, vii. pi. 6, fig. 6. 



Gen. 3. MELITA, Leach Cancer, Mont. 

 Anterior pair of legs monodactyle ; second pair with the toe 

 inflected on the middle of the plate which forms the hand ; 

 tail on each side with an elongated foliaceous lamella ; upper 

 antennae a little longer than the under. 



M. palmata, Leach. Body blackish ; antennae and legs annulated 

 with pale colour. Inhabits Devonshire coast, under stones 

 Sup. Encyc. Brit. i. pi. 21. 



Gen. 4. AMPHTTHOE, Leach. Cancer, Mont. 

 Superior antennae with no setae at the base of the fourth joint ; 

 tail simple above ; hands of the first four feet oval. 



