COMPENDIUM OF GENERIC DISTINCTIONS. 



707 



(<> >i/<i. GRAPSDS. Carapace not narrower in front than 

 behind. Middle antennae lodged under front. Hot seas. 



Genus. PLANES. Carapace longer than wide, front pro- 

 jecting. Tarsi thick and spined. Temperate and warm 

 seas. 



Tribe. OXYSTOMA TA. - Outer jaw-feet when closed 

 forming a triangular point. Outer antennas very small. 



Family. CALAPPID./E. Last four pairs of feet concealed 

 under carapace, first pair folded and coinciding with the 

 general outline. 



Genus. CALAPPA. Antennae Use those of Cancer. Claws 

 very large, compressed, and notched at upper edge, folded 

 so as to cover mouth. Warm and hot seas. 



Genus. THEALTA. Carapace rounded, with projecting 

 spikes at sides and back. Legs rather long. China. 



Genus. CAMARA. Carapace round, smooth, and wide, 

 bimple at edges. Claw-feet very flat. Mauritius. 



Family. LETTCOSIID-ffi. Outer jaw-feet when closed 

 sharp-pointed and triangular in front. Carapace more or 

 less circular. No branchial openings before froi.t-legs. 



Genus. LEUCOSIA. Internal antennas in little pits. Eyes 

 small. Shell solid. Hot seas. 



Genus. MYRA. Carapace rather egg-shaped. Front 

 limbs long. Indian seas. 



Genus. IXA. Carapace wider than long, sides prolonged 

 into cylinder or cone. Philippines. 



Genus. IPHIS. 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.33. Outer antennae very large. 

 Sternal plate long and narrow. 



Genus. CORYSTES. Carapace longer than wide, with a 

 few teeth, front forming a beak. Outer antennas longer than 

 carapace, 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. DOEIPPID^!. Fourth and fifth pairs of legs 

 elevated on back, not furnished with paddles. Eyes on 

 simple footstalks. 



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

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

 end. 



Family. CAPHYRID.33. Carapace squared, rather con- 

 vex, slightly wider than long. Eyes retractile. Sternal 

 piate rounded. 



Genus. CAPHYRA. Carapace smooth. Pincers with spines 

 on back. Front projecting. Philippines. 



Sub-order. ANOMOURA. Last, or two last, pairs of legs 

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



Family. HOMOLID^l. Carapace beaked and spinose. 

 Inner antennas 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 re- 

 ceived into branchial cavities. Warm seas. 



Genus. ECHIDNOCERUS. Carapace and limbs thickly 

 noduled. Antennas feathered. Columbia River. 



'Family. DROMIAD.ffi. Body rather globular ; front of 

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

 inner antennas very short and lodged in groove. 



Genus. DROMIA. Carapace v.Hickly covered with short 

 hairs. Two hind pairs of legs sMall, elevated, ending in 

 double claw. Many seas. 



Family. RANINID^E. Carapace large and pear-like, 

 the broader end in front. Abdomen small, but partly pro- 

 jecting. All feet except first pair fin-like. Tndian seas. 



Genus. RANINA. As Family. 



Family. HIPPID2E. All upper segments solid. Last 

 pair of legs slender and folded. First segments ->f abdomen 

 rfhort and broad, last long and triangular. Antenna plumed. 

 Pot 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. 

 Antennae close together. Last joint of second and third 

 pairs of feet flat and oar-like. Last segment of abdomen 

 long and paddle-shaped. 



Genui. HIPPA. Claws egg-shp.ped and compressed, not 

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

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

 crescentic. 



Family. PAGTTRIDJE. 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 antennae 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. BIRGOS. 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. FORCE LLANID.ffi. 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 antennas very long ; outer jaw-feet largpr. 

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

 five swimming-plates. 



Sub-order. MACROURA. Abdomen long, plated, com- 

 posed of seven segments and wUh five swimming-plates at 

 tip. First five segments mostly with a pair of false feet 

 tipped with flat fringed plates. 



Family. GALATHEID^!. No moveable plates to outer 

 antennas. Body flat. Fifth pair of legs slender, not used 

 for walking, and folded. Carapace rather wide and flat, 

 longer than broad, and beaked. Claws rathur large. Abdomen 

 larger than carapace. 



Genus. GALATHEA. Carapace covered with hniry grooves ; 

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

 Many seas. 



Family. SCYLLARID^!. Carapace wide. No moveablo 

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

 legs with one claw. Outer antennas 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. PALINURID.ffi. Body cylindrical. Outer 

 antennas 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^!. Abdomen long, not very 

 solid ; carapace small and compressed. First pair of leg* 

 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 antennas long ; small moveable 

 spine on footstalk ; inner antennas with two long bristles. 

 Claws compressed, unequal ; last joint of abdomen long and 

 triangular. Many seas. 



Genus. GEBIA. Beak triangular. Outer jaw-feet like 

 walking feet. AbJomeii wider in middle than at base ; first 

 ring with a pair of little appendages. Many seas. 



Genus. C'ALOCARIS. Carapace large, beaked. Large tri- 

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

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

 Many seas. 



Family. ASTACID.ffi. Outer antennas with moveable 

 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. Eyes 

 spherical. Basal plate of outer antennas tooth-like. Many seas. 



