70 Description of Genera and Species. 



late Government Geologist for Natal, and generousl}' presented by him to the Scottish 

 Survey Collection. 



General Description. — As in the other members of this family, the integuments are 

 thin and smooth and the form of the body is long and laterally compressed, fusiform, 

 and shrimp-like, so that it is generally found fossilised sideways. Although the test is 

 thin, it is not quite so much so as in Anthracojihausia, and the limbs are also somewhat 

 more massive. 



Seen in lateral aspect, the carapace is small and triangular and deeply emarginate 

 behind, so that while the rounded postero-lateral parts act as lappets on the epimera of 

 the first tail segment, the back of the last trunk segment is left bare. It is only slightly 

 produced into a very short blunt rostrum in front, and there are blunt protuberances 

 representing the orbital spines and at the autero-lateral angles. There is only a faint 

 suggestion of a cervical fold; the carapace, owing to its thinness, becomes wrinkled and 

 conforms to the shape of the harder internal parts when the specimen is compressed, as 

 it is usually found. Fortunately, there is a certain amount of calcareous matter in the 

 embedding rock, so that it appears to have set early after deposition, and .some of the 

 organs are preserved uncrushed. As in the other members of the family, the carapace 

 is only in vital attachment with the segments bearing the head and mouth organs, and 

 merely covers the other trunk segments loosely. The sole ornament is a narrow band 

 round the side wings and posterior margin. These limb-bearing trunk segments, 

 except the last one, are all incompletely covered in and soldered together, and, as seen 

 laterally, are wedge-shaped, but are not set at so acute an angle to the general axis of 

 the body as in Anthracophaima. The last trunk segment is comparatively free, and is 

 completely covered in by strong test dorsally. The sternal parts of this segment are 

 wide, and the articulation for the insertion of the limbs large, and far apart as seen in 

 fig. 9, the original of which, as if in illustration of the statement made above, has 

 parted from its fellows while it is still attached to its tail. 



As seen in the above ligure, the tail is massive, long, muscular, and fusiform, 

 attaining its greatest depth al)out the second segment and tapering thence evenly to the 

 base of the tail fan, the individual segments becoming increasingly long in backward 

 succession All are supplied with epimera, which are rounded on the first four seg- 

 ments. Those of the iirst segment are comparatively small, and, as already stated, are 

 overlapped by the side wings of the carapace and from behind Ijy the anterior margins 

 of the epimera of the second tail segment. These latter are large and rounded, and 

 produced both forwards and slightly backwards, so that their posterior margins overlap 

 on to the succeeding epimera. The epimera ol' the third segment are not so large as 



