Fam. PINNOTHERIDAE, _Edwards_.

Genus AMORPHOPUS, _Bell_.

CHAR. GEN.:--Corpus subcylindricum. Testa semicircularis, margine
posteriore recto.--_Antennae externae minimae_, articulo basali orbitam
subtus partim claudente.--_Antennularum fossulae_ transversae, continuae,
et ab orbitis haud separatae.--_Pedipalpi externi_ articulo quarto ovato,
palpo tri-articulato, ad angulum antico-interiorem articuli quarti
inserto.--Oris apertura antice arcuata.--_Orbitae_ apertae, margine
inferiore carente, superiore integro.--_Oculi_ transversim
positi.--_Pedes antici_ robusti, inaequales; _pedum paria secundum,
tertium et quartum_ longa, subcompressa; _par quintum_ exiguum,
simplicissimum, rudimentarium, in incisura articuli basalis paris quarti
insertum.--_Abdomen_ MARIS segmentis tertio cum quarto, et quinto cum
sexto coalitis; FOEMINAE?

Sp. unica. _Amorphopus cylindraceus_, mihi.

_Description._--The body is nearly cylindrical, somewhat depressed, the
carapace very much curved from the point to the back, quite straight
from side to side; the anterior and lateral margins forming nearly a
semicircle, the posterior margin straight; the orbits are deeply cut in
the anterior margin of the carapace, looking upwards; the inferior
margin wanting; the oral aperture much arched anteriorly; the external
footjaws with the third articulation somewhat rhomboid, the fourth
irregularly oval, and the palpi three-jointed, inserted at its anterior
and inner angle. Epistome extremely small, transversely linear; the
external antennae placed directly beneath the orbits, the basal joints
partly filling them beneath. The antennules folded transversely in large
open fossae, which are scarcely at all separated from each other, and are
open to the orbits, the eyes lying transversely; the peduncles short and
thick; the sternum is semicircular, the segments separated by very deep
grooves; the abdomen very long and narrow, the first and second joint
transversely linear, the third and fourth united and forming a triangle
truncated anteriorly at the articulation of the portion formed by the
fifth and sixth joints united, and which with the seventh form a very
narrow and linear piece extending forwards to the posterior margin of
the oral aperture; the first pair of legs robust, unequal (the right
being the larger in the only specimen at present observed); the hand in
each as broad as it is long; that of the smaller conspicuously
tuberculated, that of the l