OF THE AJ^TWEKP CEAa. 399 



3-jointed, bearing a distinct branchial appendage. Lowest seta of the branchial plate 

 of the first pair of jaws deflexed. Feet long and slender, alike in male and female. 

 Abdomen terminated by a hairy conical process ; postabdominal lobes bearing two 

 moderately long, subequal setae. 



LoxocoxcHA LATissiMA, nov. sp. (Plate LXVIII. figs. 1 a-1 d2, I e-1 h <! .) 



Carapace of the female very tumid : as seen from the side, subrhomboidal, of nearly 

 equal height throughout ; height equal to two thirds of the length ; the extremities 

 are obliquely rounded, dorsal margin almost straight, ventral sinuated in front of the 

 middle. Outline as seen from above broadly and regularly ovate, greatest width situated 

 in the middle and equal to nearly two thirds of the length, extremities mucronate. 

 Surface smooth, marked with numerous small impressed punctures, and on the anterior 

 and ventral surfaces by longitudinal striae. Length -^ inch (0-60 millim.). 



The shell of the male is longer {-^ inch) and more compressed. 



L. lafissima occurs in both beds of the Sables inferieurs and also in the " zone a 

 Biyozoaires " of the Sables moyens. It was moderately abundant in all these formations. 



LoxocoNCHA BiTEUNCATA, nov. sp. (Plate LXVIIL figs. 2 a-2 d). 



Carapace, as seen from the side, oblong, subrhomboidal ; extremities rounded, the 

 posterior produced in the middle ; dorsal margin nearly straight, ventral strongly 

 convex ; greatest height equal to fully half the length. Seen from above the outline is 

 oblong, quadrangular, with wide truncate extremities and subparallel sides, which, 

 however, bulge out in the middle ; width equal to half the length. Surface of the 

 shell covered with large and closely-set polygonal excavations. Length ^ inch 

 (0-65 millim.). 



This species was found in the Tro^hon-hed of the Sables superieurs and in the 

 Tsocardium-hed (Sables moyens). In the former it is very abundant, and in the latter 

 moderately so. It is a very well marked and distinct species, very similar in style of 

 surface-marking to L. guttata (Norman), but wholly difierent from it or from any 

 described species in the shape of the shell. 



LoxocoNCHA GKATELOUPiANA (Bosquet). (Plate LXVIII. figs. 3 a-Zg.) 

 Cythere grateloupiana, Bosquet, Entom. foss. terr. Tertiair. Prance, &c., p. 81, pi. iv. fig. 3. 



Carapace of the male {%), as seen from the side, subrhomboidal ; height equal to more 

 than half the length ; extremities obliquely rounded, the posterior bevelled off above 

 the middle ; dorsal margin straight, ventral slightly sinuated in front of the middle. 

 Outline as seen from above regularly ovate, with projecting, sharply mucronate extre- 

 mities, width about equal to the height. End view nearly circular. Surface marked 

 with moderately large subrotund pittings, which have a tendency to arrange themselves 

 in flexuous sublongitudinal I'ows, especially towards the margins of the valves. Length 

 ^ inch (0-75 millim.). 



