G36 



COMPENDIUM OF GENERIC DISTINCTIONS. 



Family. PORCELINO. -Antenna- with seven joints. 



Family. ARMADILLID-ffi.-t >val, capable of rolling up into a 

 ball. Appendages of abdomen not beyond edge. 



Heiiu^. Armadillo. — Body convex and blunt. Outer an- 

 tennae seven-jointed. Last false feet with large basal joint. 



Family. CYMOTHOAD.E.— Thorax seven ringed, free. First 

 five rings of abdomen mostly free. First three pairs of legs lor 

 .•ill strongly clawed. 



Genus. Cymothoa. — Antennae nearly equal. Eves scarcely 

 visible. Last segment of tail in a transverse square. Northern 



Tribe. FPU .1 RDITA— Males permanently minute, females 

 very large. Antennae rudimentary. Abdomen slightly de- 

 veloped. Feet very short. Mouth adapted for suction and 

 gnawing. In males, body thirteen or fourteen. jointed; one for 

 head, seven for thorax, rest for abdomen. In females, all seg- 

 ments confused together. 



Family. IONIBiE -Abdominal appendages fringe-like. 



Genus. Ioxe. — Male, body narrow and long; abdomen six- 

 jointed, each joint with a pair of membranous appendages. 

 Two pans of antenna?. Females, body pear-shaped, flat, ap- 

 pendages branched. Many seas. 



Family. BOPYRIBJE. — Abdominal appendages flat and hid- 

 lirn under abdomen. 



Serais. Bopyrur. — Male with very small antennae, very short 

 legs; abdomen with minute false legs. Female unequally pear- 

 shaped, flat, abd :n wide at base. Five pairs of false legs, 



eaeli with a triangular plate. Most seas. 



Sub-class. EntomOStraca.— Shell horny or leathery, in one or 

 more pieces. Branchiae attached to feet or jaws. Feet jointed 

 and fringed 



Legion. Branchlopoda.— Mouth formed for biting; 

 branchiae numerous, attached to feet. Body naked or buck- 

 lered. All feet with branchiae. Two- or four-jointed antennae. 

 Eyes one to three. 



or.l.r. PHYLLOPODA.— Naked or partly bucklered. Feet 

 eleven to sixty pairs, joints leaf-like, mostly respiratory. Two 

 to three eyes. 



Family. &.P0DIDS. -One pair of short antennae. Two eyes. 

 Sixty pairs of feet. Body composed of many rings, almost 

 wholly covered by shell. 



Genus. Air-. -As Family. Ponds. 



Family. BR4.NCHI0P0DIB.ff: -Body naked; two pairs of 

 antenna- lower pair prehensile in male ; eyes two, on footstalks. 

 Eleven pans of feet. 



Genus. Criooephalus. — Abdomen nine-jointed; tail with 

 two plates. Lower antennae of male cylindrical, with append- 

 ant s at base. Ponds. 



Genus. Artemia. — Abdomen long, six-jointed. Lower an- 

 tennae of male flat and without appendages. Salt-pans. 



Order. CLADOCERA.— Head projecting; body enclosed in 

 double buckler, joined on back. Four to six pairs of feet, their 

 joints cylindrical and leaf-like. Eye one. large. Antenna' two 

 pairs; lower pair large, branched and used as tins. No palpi 

 on mandibles. 



Family. DAPHNIADJE.— Upper antennae small; rive or six 

 pairs of feet; enclosed in shell. Intestine straight. 



Sub-family. Daphnin=e. — Five pairs of feet. Lower antennae 

 two-hranchpd; one branch three, the other four-jointed. 



Genus. Dafhnia.— Head produced downwards into a beak. 

 Upper antennae one-jointed, under the beak, small; lower 

 large. Ponds 



Genus. MoINA.— Head round and blunt. Upper antennae 

 one-jointed, long; lower antennae thick at base. Ponds. 



Sal '-family. Sidinae. — Six pairs of feet. Lower antennae two- 

 branched; a row of spines on edge of large branch. 



Genus. SlDA. — One branch of lower antennae three- the other 

 four-jointed. Ponds. 



Family. POLYPHEMEDJE. -Lower part of carapace empty. 

 Four pairs of feet, not included in carapace. Eye Aery large. 

 Lower antennae two-branched; one branch four- the other 

 three-jointed. 



Genus. Polyphemus. — Head distinct from body. Abdomen 

 long, projecting from shell. Eye occupying nearly whole head. 

 Ponds and ditches. 



Family. LYNCEIDJE. — Two pairs of antenna?; upper short, 

 lower branched; each branch three-jointed. Five pairs of legs. 

 One eye; abdomen jointed. 



Genus. ChydORDS. —Nearly spherical. Beak long, sharp, 

 depressed. Lower antennae very short. Ponds and ditches. 



Legion. LophyTOpoda. — Mouth formed for biting. Bran- 

 chiae few, attached to mouth. Body either with single or 

 double shield. Not more than five pairs of feet; joints cylin- 

 drical. One eye. Two pairs of antennae; one pair for locomo- 

 tion. 



Order. OSTRACODA.— Body in two-valved buckler; bran- 

 chiae on hind-jaw. No external ovary. Two or three pairs of 

 feet. 



Family. CYPRIDiE. — Antennae two pairs; upper with a pen- 

 cil of long filaments, lower thick and foot-like. One eye. Two 

 pairs of feet. 



Genus. Ctpris. — Lower antennae with pencil of long hairs. 

 Ponds. 



Family. CYTHERIDiE.— Antennae two pairs; upper not with 

 pencil or filaments. Three pairs of feet. 



Genus. Cythere. — Feet not enclosed in shell- Abdomen 

 short. Eye one. Valves in front and behind. Marine pools. 



Genu*. Cythereis. — Valves of shell oblong; edges parallel 

 above and below, and toothed or notched. Surface ridged and 

 knobbed. In sand. 



Family. CYPRIDINADS;. -Antennae two pairs, foot-like. 

 Feet two pair-, one always within shell. Eyes two, on foot- 

 stalks. Abdomen tipped with broad plate. 



C-r't'iiMs. Cypridina. As Family. 



Order. COPEPODA. -Body divided into wings; head and 

 thorax bucklered. Month with foot-jaws. Feet five pairs, 

 mostly for swimming. Ovary external. 



Family. CYCLOPIDJE.- -Head and body fused together. Foot- 

 jaws two pairs; fifth pair of legs very small. One eye. 



Genus. Cyclops.— Foot-jaws large, strong, branched. Ova- 

 ries double. Ponds. 



Genus. CanthocaMPTIIR. — Foot-jaws small, not branched. 

 Ovary single. Fresh and salt water. 



Family. CETOCHILIDiE -Head distinguishable, but fused 

 to first ring of thorax. Foot-jaws strong; three pairs. Eyes two. 



Genus. Cktochilus. -Foot-jaws not branched. Head with 

 two small pointed appendages. Thorax with six, abdomen with 

 four segments. Last pair of legs like othi rs. 



Genu* Notoiiki.i'uvs. — Thorax four, abdomen four, seg- 

 ments. Upper antennae many-jointed; lower prehensile. Foot- 

 jaws four pairs. < Ivarv large, within walls of body. 



Legion. Pcecilopoda. -Month forme, 1 for sucking. Foot 

 partly for walking or prehension, partly for swimming. Body 

 mostly enclosed in buckler. All parasitical on fishes and other 

 aquatic animals. 



Order. SI PH0N0ST0MA - -Month with tube which has 

 pointed mandibles. Thorax ringed, with several pairs of feet. 

 Foot-jaws large. 



