XANTHOPSIS. 11 



exteriore antrorsiim sensim angustiore, caulis interioris articulo secundo quadrato, 

 articulo tertio ad angiilum antico-interiorem tnincato. Pedes antici ineqviales, robiisti, 

 manu margine superiore tuberculato-cristata : reliqui graciles, simplicissimi, subcylindrici. 

 Abdomen maris articulis a tertio ad quiutum coalitis ; FCEMiNiE omnibus disjunctis. 



Tlie carapace, in all the species of this genus, is more or less convex, particularly 

 from the front backwards, and considerably so from side to side, and in every part almost 

 uniformly and deeply punctate. The nodides or elevations on the carapace vary in height 

 in the different species, but they occupy the same situations in all. There is one of 

 a depressed form on each protogastric lobe, one on the mesogastric, one more raised 

 on the metagastric, two on the cardiac region, and four on the branchial — namely, two on 

 the epibranchial lobe, and two bn the metabranchial ; the one towards the centre being 

 elongate, and often appearing like two united. The latero- anterior margin has indications 

 of the normal number of processes, namely, five, but they vary greatly in their development 

 in the different species. The front has four chstinct and strongly marked obtuse teeth, 

 including that on each side formed by the inner angle of the orbit. The outer angle 

 also forms a rounded projection, constituting the first latero-anterior process, and the 

 inferior a more acute one. The orbits are nearly round, and without fissures. The hiatus 

 is entirely filled by the basal joint of the external antennae, Avhich is quadrate, about twice 

 as long as it is broad, and extends forwards to the front, with which it is in contact. 

 The second jomt is somewhat pyriform, and has within the orbit. The antennary fossae 

 are large and open, broadly oval, and, to the extent of two thuds, filled by the basal joint 

 of the internal antenna;, which is broadly triangular, the outer margin being in contact 

 with the external antenna throughout its length, the anterior angle touching the front, 

 and the posterior margin supported by the anterior margin of the epistome. The 

 epistome is three times as long as it is broad, the central projection touching the 

 under surface of the front, and the lateral portions extending on each side to the base 

 of the external antennaj. The pterygostomian processes are deep, and veiy slightly 

 hollowed ; the anterior margin of the sternum forms an obtuse angle, and is mucronate. 

 The abdomen in the male very much resembles that in the genus Xantho. The first and 

 second joints very broad and short ; the third, fourth, and fifth united, with a slight groove 

 between each, indicating the line of union ; it is the broadest at the part answering 

 to the tliu'd segment, and gradually narrows to the anterior part of the fifth ; the sixth 

 is of the same breadth, quadrate, a httle broader than it is long ; the seventh forms 

 an equilateral triangle. The abdomen in the female is broadly oval ; the segments 

 increase regularly both in length and breadth from the first, which is very small and 

 linear, to the fifth ; the sixth much longer than the former, and rather more than twice 

 as broad as it is long ; the seventh is broadly triangular, the posterior angles being 

 obliquely truncate in some individuals. The anterior legs are very large and robust : 

 they are unequal, the right being ordinarily the larger : the first fom* joints are smooth ; 



