Goree Island, Senegambia. 261 
species now described is apparently most nearly allied to 
Ceratoplax in the characters of the orbits, antenne, and am- 
bulatory legs, but differs in the form of the carapace, the 
small epistome, and the form of the merus of the maxillipedes. 
From Typhlocarcinus nudus and T. villosus it is distinguished 
. by the form of the front, &e. 
THAUMASTOPLAX, gen. nov. 
I propose this generic name for a species in the collection 
that is closely allied in all its characters, and particularly in 
wanting the fifth pair of thoracic legs, to the genera Hexapus, 
De Haan, and Amorphopus, Bell, but is distinguished from 
the former by the much greater development of the second 
ambulatory legs and the structure of the outer maxillipedes, 
whose merus joint is elongated and narrowed at its summit, 
where it is articulated with the next joint; and from the latter 
by the well-formed orbits and the entire absence of rudimen- 
tary fifth legs. 
Thaumastoplax anomalipes, g. et sp. n. 
(PI. XIV. fig. 2.) 
The carapace is transverse, about one and a half times as 
broad as long, longitudinally rather convex, polished, naked, 
and rather coarsely punctulated above; the regions not de- 
fined; the sides sharp-edged; the antero-lateral margins 
arcuated, the margins of the branchial regions straight and 
parallel. The front is nearly a quarter the breadth of the 
carapace, and has its anterior margin nearly straight. The 
orbits are very small, without marginal fissures, with a wide 
hiatus at the mfero-internal angle, which is filled by the basal 
part of the antenne. The buccal cavity is without distinct 
longitudinal ridges on the palate; epistome obsolete; abdo- 
men in the male narrow, five-jointed, the third and fourth 
joints coalescent, and also the fifth and sixth, although in one 
specimen traces of the suture dividing the two last-mentioned 
joints are discernible under the microscope ; the sternal surface 
(an the specimens examined) is nearly naked. ‘The eyes are 
closely encased in the orbits, which have a distinct inferior 
margin ; the large antennules are transversely folded ; antennee 
with the basal portion very small and occupying the infero- 
internal orbital hiatus; antennal flagellum rather long and 
about ten-jointed. ‘The outer maxillipedes are slender and 
clothed with long dense hairs on their inner margins; ischium 
and merus each longer than broad, narrowing at each end, 
and with the inner margin arcuated; the penultimate joint 
