CHARACTERS OF FAMILIES. 19 



somite ; those of the male modified on both sides, so as to form clasping 

 organs. Posterior antennae 2 4-jointed, bearing a small secondary 

 1 4-jointed branch. Mandibles provided with a palp, which may be 

 either simple and very minute or larger and 2-branched. Maxillae 

 composed of a setiferous grasping segment and a more or less complex 

 laminar palp. First pair of foot-jaws jointed, with several marginal 

 setiferous processes ; second pair usually (not always) forming a strong 

 prehensile hand. First four pairs of swimming-feet 2-branched, first 

 pair usually unlike the rest, and converted into a prehensile appa- 

 ratus ; second, third, and fourth pairs alike or nearly so, and adapted for 

 swimming ; fifth pair foliaceous, larger in the female. Ovisac single, 

 very rarely double. 



7. CoRYC-SHD^E. Body subpyriform ; abdomen elongated, much nar- 

 rower than the cephalothorax. Anterior antennae 5 7-jointed, alike in 

 both sexes, short; posterior simple, 3 4-jointed, forming a strongly 

 clawed, prehensile hand. Mandibles, maxillae, and first pair of foot-jaws 

 mimite, destitute (or nearly so) of palps. Posterior foot-jaws prehen- 

 sible, and, in the male, powerfully clawed. First four pairs of feet 

 adapted for swimming, 2-branched. Fifth pair rudimentary, alike in 

 both sexes, rarely absent. One median eye, and usiially two large 

 simple lateral lenses. Ovisacs usually two. 



8. SAPPHIRINID^:. Body either elongated and subpyriform or broadly 

 ovate and complanate ; cephalothorax subovate and much broader than 

 the abdomen, which may be either broad or elongated and subpyriform. 

 Anterior antennae 5 7-jointed, alike in the two sexes ; posterior simple, 

 clawed or setose at the apex ; mandibles small, subulate, or very feebly 

 dentate ; maxillae small, and attached to the base of, or near to, the 

 mandible. First pair of foot-jaws setiferous at apex ; second pair 

 clawed in both sexes, but much more strongly in the male. First four 

 pairs of feet 2-branched and adapted for swimming ; fifth pair small, 

 usually 1-jointed. Ovisacs two. 



9. AKTOTBOGID^. Body broad, complanate; abdomen short, but 

 distinctly separated from the cephalothorax. Anterior antennae short, 

 9 20-jointed, those of the male often modified to a small extent for 

 clasping ; posterior short, 3 4-jointed, secondary branch (when present) 

 1-jointed. Mouth produced into a short bell-shaped, or into a long, 

 tubular siphon. Mandibles stilet-shaped, simple or provided with a 

 slender, filiform palp; maxillae composed usually of two setiferous 

 digits ; first and second pairs of foot-jaws simple, 2 4-jointed, strongly 

 clawed at the apex. First four pairs of feet 2-branched (fourth pair 

 rarely 1 -branched) ; fifth pair nidimentary or wanting. 



