OF THE ANTWERP CRAG. 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 sete. 
LOXOcONCHA LATISSIMA, nov. sp. (Plate LX VIII. figs. 1 a-ld?, le-1h¢.) 
- 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 striz. Length zy inch (0°60 millim.). 
The shell of the ma/e is longer (3's inch) and more compressed. 
I. latissima occurs in both beds of the Sables inférieurs and also in the “zone a 
Bryozoaires” of the Sables moyens. It was moderately abundant in all these formations. 
LoXoOcoNCHA BITRUNCATA, noy. sp. (Plate LX VIII. 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 go inch 
(0°65 millim.). 
This species was found in the Zyrophon-bed of the Sables supérieurs and in the 
Isocardium-bed (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 LZ. guttata (Norman), but wholly different from it or from any 
described species in the shape of the shell. 
LoxocoNCHA GRATELOUPIANA (Bosquet). (Plate LX VIII. figs. 3 a—-3 g.) 
Cythere grateloupiana, Bosquet, Entom. foss. terr. Tertiair. France, &c., p. 81, pl. 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 rows, especially towards the margins of the valves. Length 
#z inch (0°75 millim.). 
