334 On the Classification of some Biitish Fossil Crustacea. 



belong to the fossorial family in which I have placed it, the nearest 

 analogue being perhaps the recent Gebia which burrows under 

 the mud of Plymouth Sound : the fossils abounding in such a 

 state of perfection in the fine Speeton clay that they must have 

 lived in it and died in the exact spots we now find them, har- 

 monizes with this view of approximating them to those similar 

 little forms which hve habitually buried in the mud. The sub- 

 stance of the crust, though very thin, and, in the following spe- 

 cies especially, often showing signs of considerable flexibility, 

 seems rather harder than in most of the fossorial types, and the 

 strong fringe of stiif hairs at the end of the tail-pieces is in the 

 fossil replaced by semi-membranous flaps, still however strongly 

 sulcated. I have not seen the extremities of the feet ; but if, as 

 I suppose, the so-called Crangon Magnevillii of Deslongchamp 

 (Mem. de la Soc, Lin. de Normandie, t. v.) belong to this genus, 

 the four hinder pair of feet would terminate in simple pointed 

 claws, and the first pair form subcheliform pincers, having the 

 hand dilated and truncated at the extremity, which is toothed 

 and has a small spiniform immoveable finger at one end, which is 

 met by the slender moveable finger inflexed from the other end ; 

 this also agrees with the general type of the fossorial Gebia. The 

 carapace may be distinguished from Glyphaa by the branchial 

 furrow in it being very delicate and extending obliquely to the 

 posterior margin without meeting its fellow of the opposite side, 

 while in Glyphaa they are very strong and meet on the back 

 from opposite sides at an acute angle, without reaching the pos- 

 terior margin. 



Meyeria magna (M^Coy). 



Sp. Char. Carapace about 2^ inches long and 1 inch 2 lines 

 deep at the middle of the side ; three strong tuberculated lon- 

 gitudinal ridges on each side of the cephalic part of the cara- 

 pace ; from about the middle of the deep nuchal furrow a row 

 of small tubercles extends halfway to the posterior margin, 

 and higher up (bordering the intestinal region) a similar row 

 on each side extends from the posterior margin nearly half- 

 way to the nuchal furrow -, rest of the carapace covered with 

 minute sharp granules, about four in a space of three lines at 

 the middle of the sides; r ostium short, pointed; abdomen 

 about 3|^ inches long, each segment with about four irregular, 

 single, crowded rows of granules disposed longitudinally, the 

 broad intervening spaces nearly smooth ; a few irregular groups 

 of granules on the extremities ; the last segment granulated 

 like the carapace ; tail-flaps broad, rotundato-trigonal, finely 

 fimbriated at the ends, each with a strong mesial ridge ; 

 transverse suture of the outer pair strongly marked, serrated ; 



