COMPENDIUM OF GENERIC DISTINCTIONS. 



795 



sharp-pointed and triangular in front. Carapace more or less ' 

 circular. No branchial openings before front-legs. 



Genus. LBUCOSIA. Internal antenna; in little pits. Eyes 

 small. Shell solid. Hot seas. 



Carapace rather egg-shaped. Front limbs 



Genus. MYRA. 

 long. Indian seas. 



Gtnus. Ix A. Carapace wider than long, sides prolonged 

 into cylinder or cone. Philippines. 



Genus. I PHIS. Carapace rhomboidal. Conical spurry 

 points on each side. Philippines. 



Genus. EBALIA. Carapace rhomboidal, knobbed. Abdo- 

 men seven-jointed, in male narrow, in female broad ; last joint 

 very small. Temperate and warm seas. 



Genus. NURSIA. Carapace rhomboidal, sides angulated or 

 scooped. Indian Ocean. 



Family. CORYSTID^E. Outer antennas very large. 

 Sternal plate long and narrow. 



Genus. CORYSTES. Carapace longer than wide, with a few 

 teeth, front forming a beak. Outer antenna; longer than cara- 

 pace, with row of long hairs on upper and lower edges. Fore- 

 legs of male very long. Temperate and warm seas. 



Genus. THIA. Carapace smooth, heart-shaped, narrow 

 behind, front projecting. All legs small. Temperate and warm 

 seas. 



Family. DORIPPID^E. Fourth and fifth pairs of legs 

 elevated on back, not furnished with paddles. Eyes on simple 

 footstalks. 



Genus. DORIPPE. Claws small, short, and equal ; third 

 pair of feet largest, two last pairs having a hooked nail at end. 



Family. CAPHYRIDvE. Carapace squared, rather con- 

 vex, slightly wider than long. Eyes retractile. Sternal plate 

 rounded. 



Genus. CAPKVKA. Carapace smooth. Pincers with spines 

 on back. Front projecting. Philippines. 



Sub-order. AXOMOURA.\A&\. t or two last, pairs of 

 legs not used for walking, and are set above level of other legs. 



Family. HOMOLID^E. Carapace beaked and spinose. 

 Inner antennae long. Fifth pair of legs not used for walking. 



Genus. HOMOLA. A series of sharp spines set radiately on 

 the carapace. Eye-footstalks short, eyes very large and round. 

 Mediterranean. 



Genus. LITHODES. Carapace thickly spined. Beak very 

 long. Fifth joint of outer jaw -feet oblong. Hind-legs received 

 into branchial cavities. Warm seas. 



Genus. ECHIDNOCERUS. Carapace and limbs thickly 

 noduled. Antennae feathered. Columbia River. 



Family. DROMIADjE. Body rather globular; front of 

 carapace bent down. Eyes short and looped in their orbits; 

 inner antennae very short and lodged in groove. 



Genus. DROMTA. Carapace thickly covered with short 

 hairs. Two hind pairs of legs small, elevated, ending in double 

 claw. Many seas. 



Family. RANINIDjE. Carapace large and pear-like, the 

 broader end in front. Abdomen small, but partly projecting. 

 All feet except first pair fin-like. Indian seas. 



Genus. RANINA. As Family. 



Family. HIPPID/E. All upper segments solid. Last 

 pair of legs slender and folded. First segments of abdomen 

 short and broad, last long and triangular. Antennas plumed. 

 Hot seas. 



Genus. ALBUNEA. Claws triangular, compressed. Last 

 joint of next pairs of feet hooked. Carapace flat, squared, but 

 rounded behind ; toothed in front. 



Genus. REMIPES. Claws rather long, conical, and feeble. 

 Antennas close together. Last joint of second and third pairs 

 of feet flat and oar-Ike. Last segment of abdomen long and 

 paddle-shaped. 



Genus. HIPPA. Claws egg-shaped and compressed, not 

 fingered. Eye-footstalks long and thread-like. Last joint of 

 second and third pairs of feet triangular, of fourth pair cres- 

 centic. 



Family. PAGURID^E. Abdomen soft, and nearly mem- 

 branous. Two hind pairs of legs very short. 



Genus. PAGURUS. Abdomen turned on itself, a pair of 

 unsymmetrical appendages at tip. Inner antenna; short. 

 Most seas. 



Genus. CENOBITA. Antennas advanced; middle pair nearly 

 as long as outer. Thorax egg-shaped, conical, long, narrow, 

 and greatly compressed. Indian Ocean. 



Genus. BIRGUS. Abdomen rather solid, having two rows 

 of flattened appendages beneath. Fourth pair of feet about 

 half as large as third pair. Thorax heart-shaped. Indian 

 Ocean. 



Family. PORCELLANID^E. Tail ending in swimming- 

 plates. Fifth pair of legs small and folded. Sternal plate wide 

 and circular. 



Genus. PORCELLANA. Carapace wide as long, flattened 

 above. Outer antennae very long ; outer jaw-feet larger. 

 Claw-legs large and flat. Abdomen wide ; seven segments ; 

 five swimming-plates. 



Sub-order. MACROURA.Ab&omtn long, plated, com- 

 posed of seven segments and with five swimming-plates at tip. 

 First five segments mostly with a pair of false feet tipped with 

 flat fringed plates. 



Family. GALATHEID^E. No movable plates to outer 

 antennae. Body flat. Fifth pair of legs slender, not used for 

 walking, and folded Carapace rather wide and flat, longer 

 than broad, and beaked. Claws rather large. Abdomen larger 

 than carapace. 



Genus. GALATHKA. Carapace covered with hairy grooves ; 

 beak extended ; eyes large ; no orbit. Abdomen extended. 

 Many seas. 



Family. SCYLLARID^E. Carapace wide. No movable 

 plate to outer antennae. Fifth pair of legs not folded. All 

 legs with one claw. Outer antennae large and flat ; abdomen 

 very wide ; swimming-plates partly flexible. In male, first pair 

 of false feet very large, with two wide plates ; rest with one 

 plate. Many seas. 



Genus. SCYLLARUS. Carapace larger than wide; sides 

 parallel. Many seas. 



Genus. IBACUS. Carapace wider than long, deeply cleft on 

 either side, notched all round. Abdomen with ring-plates, flat, 

 pointed, and wide. Indian seas. 



Family. PALINURIDjE. Body cylindrical. Outer an- 

 tennas thick and long ; basal joint very large. Feet with single 

 toe. Sternal plate wide. 



Genus. PALINURUS. Carapace spiny, with three horns in 

 front. Many seas. 



Family. THALASSINID-iE. Abdomen long, not very 

 solid; carapace small and compressed. First pair of legs large. 

 Sternal plate long and narrow. 



Genus. CALLIANASSA. Carapace very small, not beaked. 

 Eye-footstalks flat. Third pair of legs wide at end; second 

 pair with two toes. One claw much larger than the other. 

 Many seas. 



Genus. Axius. Outer antennae long; small movable spine 

 on footstalk ; inner antenna; with two long bristles. Claws 

 compressed, unequal ; last joint of abdomen long and triangular. 

 Many seas. 



Genus. GEBI A. Beak triangular. Outer jaw-feet like walk- 

 ing feet. Abdomen wider in middle than at base ; first ring 

 with a pair of little appendages. Many seas. 



Genus. CALOCARIS. Carapace large, beaked. Large tri- 

 angular scale at base of outer antenna:. Claws long, flat, and 

 slender. Eyes very small, without any pigment on cornea. 

 Many seas. 



Family. ASTACID^E. Outer antennae with movable 

 plate at base. Beak moderate, just hiding base of eye-foot- 

 stalks. Claw-feet large ; second and third pairs of feet two- 

 clawed; fourth and fifth one-clawed. Side of each abdominal 

 ring extended. Cross-joint in each swimming-plate. 



Genus. HOMARUS. Beak narrow, with several teeth. Eye* 

 spherical. Basal plate of outer antennae tooth-like. Many 

 seas. 



Genus. ASTACUS. Beak wide at base, depressed; one 

 tooth on each side. Fresh running waters. 



Tribe. CA RID IT A .Abdomen very large, horny. Outer 

 antennae with very large plate at base. Base of false feet 

 covered by projections of segments. 



Family. CRANGONID^J. Both pairs of antennas on same 

 line. First pair of legs with small pincers. 



Gtnus. CRANGON. Carapace flattened ; claw also flattened. 

 Second and third pairs of legs very slender ; fourth and fifth 

 strongest. Many seas. 



