THENOPS. 33 



OKTi'E.^—MACRURA. 

 Sub-Order— CATAPHRACTA. 



Family— ^CYlAjkRVdM. 

 Genus — Thenops, Bell. 



Char. Gen. Testa depressa, sinu cervical! profundo in partes insequales divisa, 

 margine anteriore quinque-lobato, rostro prominente, e dentibus binis, conicis, fortibus 

 formato. Antenna externoe planae, margine exteriore fortiter dentato. Fedipalpi externi 

 graciles, filiformes. Abdomen triedrum, carinatum. 



Species unica. Thenops scyllariformis, miJii. Plate VII, figs. 1 — 8. 



Descr. Carapace flattened, the surface coarsely granulated, divided at about one 



third from the front by the cervical furrow, which is very deep, strongly curved forwards ; 



the anterior portion or cephalic arch with a short, central, longitudinal fiuTow, commencing 



at the cervical sulcus, and circumscribed by two carinse, which converge forwards into a 



short carina which is bordered by two others ; on each side a strong curved ridge runs 



from the anterior margin backwards to the cervical furrow. The central portion of the 



margin is furnished with four or five large flattened lobes, the exterior portion denticulate, 



and terminating outwards in an acute angle; the rostrum arises immediately under and 



in front of the median lobes of the carapace, and consists of two very strong, conical, 



acute, slightly divaricating teeth ; the lateral margin thick, strongly granulated, and 



toothed ; the post-cervical portion or scapular arch is flat, and has three carinse, one 



central, the others marginal; the granulations of the surface coarser than those of the 



anterior portion, and almost squamiform. The external antennae have the remarkable 



conformation peculiar to the family Scyllaridse, being broad and much flattened, the 



external margin strongly toothed ; the abdomen is carinated and- tectiform, the segments 



coarsely punctate, and each with an obtusely triangular, transverse ridge ; the epimera 



denticulate on the margin. The caudal appendages are either wholly wanting, or in 



too nuitilated a state, in all the specimens I have seen, to admit of any description. 



The legs are compressed, the anterior ones considerably the largest; the external 



pedipali)s slender, filiform, and curved inwards towards the extremity ; the thorax forms 



an acute triangle, and there are a pair of deep depressions at the junction of the diSerent 



segments. 



