SCYLLARIDIA. 35 



Genus — Scyllaridia, Bell. 



Char. Gen. Testa seque longa ac lata, suleo cervicali profundo, rostro dilatato, 

 bidentato. Oculi prope angulum antico-lateralem positi. Abdomen medio elevatum, 

 haud carinatum. 



Species unica. Scyllaridia Koenigii, mihi, Plate VIII, figs. 1 — 3. 



Cancer (Scyi/larus?) tuberculatus, Konig. Icon. Foss. Sect., fig. 54. 

 Xanthopsis tuberculatus, Morris. Cat. Brit. Foss., 1854, p. 116. 



Descr. Carapace very nearly as broad as long, coarsely granulated ; frontal margin 

 nearly straight, denticulated ; the rostrum flattened, somewhat expanded, bidentate ; 

 orbits placed near the external angle, but not at the extremity as in Thenus; upper 

 and inner orbital margin elevated; cervical furrow deep, smooth, commencing on the 

 lateral margin, about one fourth from the anterior angle, and passing obliquely backwards 

 to about the middle of the carapace ; gastric region with an elevated ridge on the centre 

 having two angular projections, of which the posterior is the more prominent, and 

 a small tubercle on each side; cardiac region with a strong ridge similar to that of 

 the gastric, terminating abruptly at the cervical furrow ; branchial region with two 

 slightly tuberculated ridges, the outer one marginal. Basal joints of the external antennae 

 broad and flattened, as in the other genera of this family ; abdomen rounded, raised in 

 the centre, but not carinated ; the segments granulated, excepting on that portion of each 

 which passes under the one in front of it. 



In all the specimens yet discovered, the abdomen is bent under the thorax. 



Length of carapace, 14 inch; breadth, 1'4 inch nearly. 



Obs. All the specimens hitherto obtained of this species are from Sheppey. The original 

 one, to which further allusion will presently be made, is in the British Museum. There 

 are four in the collection of Mr. Bowerbank, and one in that of Mr. Wetherell. In all of 

 these the limbs and the caudal extremity of the abdomen are either wholly wanting 

 or existing only in unavailable fragments. There are, however, sufficiently perfect 

 remains of other parts, to afford data for its association with Thenops in the family 

 Scyllaridae, and for its generic distinction from that and from the recent forms of the 

 family. Its nearest approximation is to the recent genus Scyllarus, from which it is 

 sufficiently distinct by the form of the rostrum, the depth and distinctness of the cervical 

 furrow, and the rounded form of the abdomen. Its relation to that genus is, however, 



