ON TWO NEW GENERA OF CRUSTACEOUS ANIMALS, DISCOVERED BY MR. JOHN CRANCH IN THE EXPEDITION TO CONGO.

MALACOSTRACA.

Odontorynchus.*

Thorax antice rostratus; rostrum acuminatum utrinque alternatim dentatum. Lamellæ caudales magnæ elongatæ foliacea postice latiores apice rotundatæ. Pedum par anticum minutum, bifidum; secundum longius bifidum; tria postica multo largiora, simplicia. Antennæ interiores bifidæ ; articulo secundo multiarticulato; exteriores acuminatæ paululum longiores multiarticulatæ.

Thorax anteriorly rostrated; rostrum acuminated on each side alternately dentated. Caudal lamellæ large, elongated, foliaceous behind broader, with the extremities rounded. Anterior pair of feet minute bifid; second pair longer bifid; hinder pair much larger simple.

Interior antennæ bifid; the second joint many jointed.

* wdovrweis dentatus, et puyxos, rostrum. It belongs to the family Squilladæ.

Odontocerus lutescens.

0. Corpore toto, antennis, pedibus, lamellisque caudali

bus luteis.

Longitudo 0052 mellemetrorum.

Habitat ad Guineæ littora.

O. With all the body, antennæ, feet and caudal lamellæ clay-coloured.

Length 23-12 of an inch.

Inhabits the shores of Guinea.

Prionorhynchus,*

Thorax convexus, elongatus, antice rostratus; rostrum utrinque ultra medium serratum; postice filamento corneo acuminato largo instructus. Pedum par anticum tenue bifidum acuminatum; paria quatuor, postica æqualia unguibus trifidis instructa. Lamellæ caudales æquales ovatæ foliaceæ. Oculis magnis.

Antennæ interiores bifidæ, multi-articulatæ acuminata; exteriores, longiores acuminate multi-articulatæ.

Thorax convex, elongated, anteriorly rostrated; rostrum on each side beyond the middle, serrated; with a long horny acuminated filament behind. First pair of feet acuminated, slender and bifid; the four hinder parts equal with trifid nails; caudal lamellæ equal, oval, foliaceous; eyes large.

Interior antennæ bifid, many jointed, acuminated; exterior antennæ ; longer, acuminated, many-jointed.

O', seira, et puyxos, rostrum.

Prionorhynchus Cranchianus.

P. Thorace, rostroque gilvo auro variegatis; filamento corneo sanguineo; antennis, pedibus, abdomineque carneis pallidis; oculis aureis.

Longitudo 0021 millemetrorum.

Habitat in Mari Atlantico. Lat. 24°. 13'. Long. 18°. 51'. 15".

P. With the thorax and beak carnation variegated with gold; the horny filament deep blood red, the antennæ, feet and abdomen, pale red; eyes golden.

Length 91-12 of an inch.

Found in the Atlantic ocean. Lat. 24°. 13. Long. 18. 51'. 15". on the surface of the sea.

ON THREE NEW GENERA OF THE MALACOSTRACEOUS CRUSTACEA, BELONGING TO THE FAMILY SQUILLADE, BY WILLIAM ELFORD LEACH, M. D. F. R. S. &c. HONORARY MEMBER OF THE PLYMOUTH INSTITUTION.

Opithiocheirus.*

Antennæ duæ elongata, quatuor-articulatæ; articulo ultimo acuminato multiarticulato tertio, externe filamentis duabus æqualibus acuminatis multarticulatis instructo.

Pedum paria tria antica simplicia æqualia ambulatoria, par quintum laius compressum, manu uni-dactylo interne denticulata, instructum.

Antennæ two, elongated, four-jointed; the last joint acuminated many-jointed; the third joint externally furnished with two equal acuminated many jointed filaments.

Feet, the three anterior pair simply formed for walking, the fifth pair broader compressed, furnished with a monodactyle hand internally denticulated.

Opithiocheirus Chrysophthalmus.

O. Thorace antennis, pedibus et oculorum pedunculo, croceo testaceo marmoratis; oculis aureis, pupillo nigrescente; abdomine segmentis postice, et manus aspectu interno, aureis.

Odioc, posticus, et yep, menus.

Longitudo 0042 millemetrorum.

Habitat in mari Atlantico prope fluvii Congoensis os.

O. With the thorax, antennæ and peduncle of the eyes marbled with saffron and testaceous (clay colour;) the eyes golden, with a black pupil; the same segments of the abdomen behind, and the internal aspect of the hand golden.

Length 17-12 of an inch.

Inhabits the Atlantic ocean near the river Congo.

Usterocheirus.*

Antennæ quatuor internæ bifide; setæ acuminatæ multiarticulata; externæ longiores acuminatæ multiarticulatæ.

Pedum paria quatuor, anteriories æquales, acuminata, pedipalporum exteriores (qui etiam sunt acuminati) multo longiora, par quintum latius compressum manu uni-dactylo inermi instructum.

Antennæ four, the internal ones bifid; the setæ acumi.nated many-jointed; external ones longer, acuminated, multiarticulated.

Feet; the four anterior pair equal acuminated, much longer than the exterior pedipalpi (which are also acuminate) the fifth pair broad compressed, furnished with a mono-dactyle unarmed simple hand.

Usterocheirus Macropocoilium.+

U. Thorace, antennis, oculis, pedipalpis, pedibus abdomine

* sepos posterior, et xip, manus.

† μακρος, longus, et ποκιλιον, abdomen.