58 
ON THE BRACIIYUROUS DECAPODS OF THE CAPE. 
Feet, first pair thicker than the rest, and having the digits serrulated on the inside ; the second 
pair longer than the first, and, as well as the three posterior pair, it is furnished with a 
subcheliform penultimate joint, which is truncated at the apex, and unidentated. 
Abdomen of male has seven segments. 
Tins groupe is in the family Mithracidce exactly what Acanthonyx is in the family Epial- 
tidce. Both are analogous groupes in contiguous families ; but whether they ought to be con- 
sidered as sub-genera, or only sections of sub-genera, remains yet to be discovered. 
Sr. 4. ( ) Dchaanius acanthopus, n. s. 
Descr. Dehaanius test!! glabra, margine laterali antice tridentato, dente medio majore, ciypeo 
fossula inter dentes duos medios majores longitudinali. 
Note. Carapace pyriform and without hair, having the digestive, cardiac, and branchial 
regions distinct. Anterior lateral margin tridentate, the middle tooth being much the largest. 
Clypeus short, with four triangular divergent teeth, the two in the middle being the largest 
and farthest advanced. From the middle bifurcation of the clypeus there is a deep groove 
continued about half its length backwards. The feet are without hairs. The chelse of fore- 
feet are thick, and serrulated on the inside. The other four pair of feet have thick knees, and 
subcheliform claws. The only specimen brought home by Dr. Smith has lost of the external 
antenna; all but the two first joints. 
Sub-genus, Mithrax, Leach. 
Sp. 5. ( ) Mithrax quadridentatus, n. s. 
Descr. Mithrax cornubus rostri divergentibus ad apicern arcuatis, extus bidentatis dente apicali 
multo majore ; testa triangulari supra granulosa, haud spinosa, marginibus latcralibus anticis 
quinquidentatis. 
Note. Carapace and feet exactly like those of Mithrax dichotomus, Lat., to which this species 
comes exceedingly close. The anterior lateral edges of the shell are armed on each side, 
as in M. dichotomus, with seven spiniform teeth ; but the hinder two of these teeth are evanescent, 
and are placed more on the back. There are, moreover, no points on the hinder edge of 
the carapace, as in M. dichotomus. The eyes are globular, and larger than the base of the 
pedicles. The antennary fossa has no tubercle at the posterior edge. The anterior feet are 
long, having the third and fourth joints covered with short spines : the fifth joint or hand is 
slender and smooth, as is also the moveable finger without teeth. The other feet have no 
tooth at the extremity of the third joint. The size is 1| inch. . 
6. By means of Eurynome we proceed to the Parthenopina ; but of this groupe no species 
has been brought from the Cape ; so we avail ourselves of Cryptopoda to pass on to JEthra, 
and so among the Cancrina, of which the families appear to be as follow. All these families are 
distinguished by having the scapes of the palpi of the fifth maxilla; unidentated on the outside ; 
and their males have the genital orifices hollowed out in the first joints of the hind feet. 
