CHARACTERS OF FAMILIES. 



1. CALANID.S!. Body elongated; abdomen distinct from thorax; 

 anterior antennas long, 24- or 25-jointed, that of the male, on the right 

 side only, partially thickened and geniculated ; posterior antennae large, 

 and usually 2-branched ; mandible-palp usually 2-branched. Both 

 pairs of foot-jaws large and well developed, many jointed, marginally 

 setiferous. First four pairs of feet 2-branched, outer branches 3-jointed ; 

 fifth pair similar to the foregoing pairs, or much modified (especially in 

 the male) and unlike on the two sides. Ovisac single. 



2. MISOPHKIID.S;. Like Calanidae, but that the anterior antennae are 

 composed only of 7 18 joints, and are much shorter than the cephalo- 

 thorax ; robust, and in general build decidedly cyclopoid. 



3. CYCLOPIDJE. Cephalothorax ovate and usually much more robust 

 than the abdomen ; anterior antennae seldom longer than the cephalo- 

 thorax ; those of the male alike on both sides and modified for the 

 purpose of clasping ; posterior antennae unbranched. Palps of mandi- 

 bles and maxillae usually well-developed. Foot-jaws mostly less deve- 

 loped than in Calanida. First four pairs of feet as in Calanidce ; fifth 

 pair rudimentary, alike in both sexes, and usually 1-jointed. Ovisacs 

 two. 



4. NOTODELPHYID.S:. Fourth and fifth body-segments of the female 

 usually coalescent, swollen dorsally to form a matrix or covering for 

 the ova after their passage from the ovarium. Anterior antennae short, 

 5 15-jointed; posterior unbranched, 3-jointed. Mandible-palp 2- 

 branched. Foot-jaws and swimming-feet like those of Oyclopidce. Fifth 

 pair of feet rudimentary or altogether absent. No external ovisac. 



5. BUPRORID.E. Body pouch-like, not distinctly segmented. An- 

 tennae rudimentary, anterior 2- or 3-, posterior 1- or 2-jointed. No 

 mandible-palp. Mouth-organs minute; maxillae and foot-jaws short, 

 broad, and adapted for chewing or grasping. Feet very small, papilli- 

 f'orrn, 2-branched ; no external ovisac ; abdomen very small, furcate. 

 All the appendages of the body very small and imperfectly developed. 



6. HARPACTICID^;. Body sometimes complanate, but usually cylin- 

 drical; abdomen not sharply separated from the thorax. Anterior 

 antenna short, 4 10-jointed, length scarcely exceeding that of the first 



