1857.] 



GOULD TROPIFER L^VIS. 



361 



to the notice of the Society this small Decapod, which has heeii 

 kindly lent to the Geological* Survey hy E. Higgins, Esq., of Birken- 

 head. 



TrOPIFER L.EVIS. 



Carapace. — The carapace in this specimen (fig. 1, 6, & fig. 3) is 

 somewhat flattened and subrectangular, and has the posterior angles 

 slightly produced ; the length is rather more than 3 lines, and the 

 width, w hich is pretty constant throughout, 2f lines ; it has three 

 longitudinal ridges, one median and the others nearly parallel to it, 

 but rather sinuous, and about equidistant between it and the lateral 

 margin of the carapace, which is slightly thickened and crenulated, 

 as are also the ridges. 



Figs. 1, 2, & 3. — Tropifer laevis, //'om the Lias Bone-bed at 

 i Aust Passage. 



Fig. 2. 



Fig. 3. 



Fig. 1. Enlarged view of the specimen ; the natural length is shown by the line 

 at the side. a. Fragment probably of one of the limbs ; b. Carapace ; 

 c. Four abdominal segments. 



Fig. 2. Two of the abdominal segments ; magnified : — a, the first ; b, the second 

 segment. 



Fig. 3. Side-view of the specimen, in outline, magnified. 



The cervical furrow is distinct, cutting the median ridge at a little 

 more than one-third from the posterior end ; its general direction is 

 outwards and forwards to the edge of the carapace, which it meets at 

 about two-fifths from its anterior end ; each half is divided into two 

 portions by the lateral and longitudinal ridges : the outer portion is 

 straight and the inner curved, with the convexity forwards, and from 

 its most advanced point, an indistinct line runs forwards and inwards 

 to the central ridge, giving rise to a deltoidal figure, in which the acute 

 angle is anterior. 



The front edge of the carapace is imperfect, but enough remains 

 to show that it is truncate and emarginate beneath the lateral ridges, 

 and rather outside of them, for the reception of the large eyes. One 



