320 PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [Mar. 18, 



curving upwards, armed with a double row of conical, slightly curved 

 spines, nearly -i- inch in length, and extending back to the cervical 

 furrow, thence in a single row down the median line of the carapace 

 to the posterior margin. Cervical furrow broad and strong, termina- 

 ting in a smooth rounded sinus near the antero -lateral margin ; the 

 branchial region divided from the gastric by two slender parallel 

 furrows, which, passing obliquely down the sides of the carapace, 

 unite with the cervical furrow near the margin. The posterior and 

 lateral borders of the carapace are raised, and have a sulcus within 

 the margin ; the surface of the posterior portion is scabrous, of the 

 anterior portion finely punctate, the antero-lateral portion being 

 covered with minute irregular spines. Two lines of minute spines 

 extend forward from the cervical furrow obliquely on each side of the 

 median furrow towards the rostrum, and another line extends back- 

 wards and upwards from the posterior margin of the same furrow, on 

 either side, obliquely to the median line. Eye globular (?), and, from 

 the size of the orbit, probably large. Outer pair of antennae large, 

 multi- articulate, 4 to 5 inches long; three basal joints large and 

 armed with spines. Inner antennae smaller, multi-articulate ; basal 

 joints crushed, and insufficient for description. 



The legs forming the first pair are symmetrical, and equal in length 

 to the entire body ; they are scabrous, and armed with several 

 rows of smooth, strongly curved spines ; extremities monodactyle, 

 the fixed ramus of the penultimate joint being only represented 

 by a large spine one -fourth the length of the ultimate joint, which is 

 curved and pointed. The limbs of the second pair are also armed 

 with spines along their margin ; the penultimate joint is flat and 

 very broad at the distal extremity, the ultimate joint small and 

 pointed. Third and fourth pairs like the second, but nearly smooth. 

 The fifth pair is much smaller than the rest, and only very imper- 

 fectly preserved. Abdomen rather longer than the cephalothorax. 

 The epimeral portion of the first segment much less produced, and of 

 the second segment much more produced, than in those succeeding ; 

 all the segments minutely punctate at, and spinous upon, their 

 lateral margins. Each segment deeply curved in front to receive a 

 small polished ball- articulation attached to the posterior margin of 

 each joint of the abdomen. The tail-lobes are broad, the outer 

 lamina having a crescent-shaped division near its extremity, bor- 

 dered by 2 or 3 spines ; the inner lamina is smooth, and the central 

 lobe slightly punctate, with 2 or 3 small spines along its margin. 



False abdominal legs apparently fitted for natation ; but two only 

 are preserved, and those very imperfectly. 



Dimensions. — Length of the carapace 3-1- inches ; greatest depth 

 1-| in. (in profile). Length of the rostrum | in. Depth of the first 

 abdominal segment |- in., of the second ■£ in. Length of the abdomen 

 and tail-lobes 3 J in. Length of the outer antennae 4-5 in. Length 

 of the fore-arm 2-| in., wrist f in., hand 2 in., finger 1-| in. 



Length of a detached hand and arm: — arm 2| in., wrist -J in., hand 

 2| in., finger 2-i- in. 



