1852. | 9 
armatis, paris postici apice setis longiusculis instructis.—Typus est Monoleprs 
spinitarsus, Say. Hie pertineret quoque Meg. mutica, Desm. si ejus pedes postiei 
setis longiusculis confecti; aliter genus alterum instituendum. Verbum ‘ Ma- 
restia’? clarissimum Desmarest commemorat. 
3. Mecanora, Leach.—Carapax fronte simpliciter rostratus, rostro vix 
deflexo, acuto. Pedes 8 postici ad basin infra uni-spinigeri: 5ti minores, tarso 
styliformi.—Typus Meg. Montagut, Leach.” 
4, Cytienr, Danaz.—Carapacis frons uti in Megalopa. Pedes 8 postici ad 
basin infra uni-spinigeri; 5ti minores, tarso anguste lamellato, setis longiusculis 
partim ciliato. 
5. Trisoua, Dana.—Carapax fronte horizontalis tricuspidatus, rostro (vel 
cuspide mediana) tenui, cuspidibus (vel dentibus) externis vix longiore. Antenne 
interne inter rostrum et cuspides externas aperté inflexe. Pedes postici minores, 
tarso unguiculato setisque longis non instructo. 
Descriptiones Megalopideorum adhue inedite. 
MarESTIA ELEGANS.—Carapax antice angustus et superne visus bilobatus, late- 
ribus fere parallelis, pone oculos vix salientibus. Pedes antici parvi, manu 
oblonga, margine inferiore et partim superficie interna remote hirsutis. Pedes 
2di marginibus sparsim ciliati, tarso infra 7-spinoso, ad basin tuberculum infra 
non gerente. Tarsi postici infra 6-spinosi, apice unguiculati et 4 setis longis 
instructi. Hab. Promontorio Bone Spei. Long. Carapacis 4—5’”. An Megalopa 
mutica Krawssit (Stdaf. Crust. p. 54) et De Haanii (Faun. Japon. p. 167) ? Sed 
pedes postici extremitate setis tarso paulo longioribus instructi. 
Marestra ATLANTICA.—Carapax antice angustus et superne visus bilobatus, 
lateribus postice paulo divergentibus, pone oculos vix salientibus. Pedes an- 
tici parvi, manu oblonga, nuda aut nudiuscula. Pedes 6 sequentes nudiusculi, 
tarso infra quinque spinas tuberculumque ad basin instar calcis gerente. 
Tarsi postici parvuli, sed setularum duabus paribus infra instructi, non spinosi, 
apice unguiculati et tribus setis longis armati.—HaB. lat. aust. 6°, long. occ. 24°. 
~ Marestta PERVALIDA.—Carapax antice latus et superne visus obsolete quadri- 
lobatus, lobis subequis, lateribus postice non divergentibus, prope medium uni- 
dehtatis. Pedes antici pervalidi, manu valde crassa, tumida. Tarsi postici 
infra spinosi, apice tribus setis longiusculis armati.—Had. lat. bor. 6°, long. 
orient. 1732. 
MoNoLEPIS ORIENTALIS.—Sterni segmenta fossam sterni includentia antica mar- 
gine interiore fere truncata, vix triangulata; segmenta proxima convexa, non tu- 
berculigera. Tuberculus medianus inter aream buccalem et fossam sterni simpli- 
citer subtriangulatus, antice acutus, postice hemisphericus, utrinque depressione 
deinde septo brevi antice et oblique producto cinctus. ‘Tarsus pedis postici 
brevis, non unguiculatus, apice tribus setis longiusculis armatus, infra setulis 
paucis perbrevibus necque spinis instructus. Had. in mari Suluensi. Long. 
carapacis 4/’”.—M. inermis differt, sterni sezmentis anticis intus non subtruncatis 
sed prominenter triangulatis, proximis unituberculatis, tuberculo mediano inter 
aream buccalem et fossam sterni tuberculis tribus composito.} 
CyLLENE HYALINA.—Rostrum parce prominens. Carapax subovatus, lateribus 
pone oculos paulo saliens, postice inermis. Thorax infra ad extremitatem pos- 
* Malac. Pod. Brit. pl. 16. Leach describes three other species, (not noticed by 
Edwards,) in Tuckey’s Exped. to the Zaire, (London, 1818,) p. 404. The MM. 
Cranchit may be a true Megalopa; the others have a deflexed beak. 
+The author is indebted to Prof. L. R. Gibbes, of Charleston, S. C., for the 
privilege of examining specimens of the M. inermis. They were obtained by him 
from the stomach of a fish off the Atlantic coast between New York and Charleston, 
in 1846. See Rep. Crust.in U.S. Collections, by Prof. Gibbes, in Proc. Amer. 
Assoc. Charleston, 1850, vol, iil. p. 192. 
