18 ' MR. J. CARTEE ON THE PALEONTOLOGY OF [Peb. 1 898, 



II. Beachytjea. 



Family Dromiacea. 



Genus Gasteosacus, H. v. Meyer. 



Gasteosacus Wetzleei, H. v. Meyer, 1854. (PI. I, fig. 3.) 



1854. Gastrosacus Wetzleri, H. v. Meyer, ' Jurass. u. Trias. Crust.,' Palaeonto- 

 graphica, vol. iv, p. 51 & pi. x, figs. 3 & 4. 



1858. Fj'osopon aeuleatum, Quenstedt, ' Der Jura,' p. 779 & pi. xcv, figs. 46 & 47. 



1860. Gastrosacus Wetzleri, H. v. Meyer, ' Die Prosoponiden,' Palaeontographica, 

 vol. vii, p. 219 & pi. xxiii, fig. 34. 



1867. Prosopon actdeatum, Quenstedt, ' Handb. d. Petrefaktenkunde,' p. 315 & 

 pi. xxvi, fig. 14. 



Description. — Length, from base to rostrum, one-sixth greater 

 than the width. Surface minutely granulated. The rostrum occupies 

 the median third of the orbito -frontal border ; it is acutely pointed, 

 and about one-fourth the length of the carapace ; it bears a sharp 

 granulated dorsal carina. Orbits rather small, with thin margins. 

 Cephalic area somewhat smaller than the scapular. Surrounding the 

 gastric lobes is an unusual annular sulcus, bearing granules which tend 

 to assume a radiate or linear arrangement ; an indistinct radiate 

 depression divides this area into four portions : — the normal branchial 

 lobes separated by slight sulci ; the linear urogastric lobe ; and the 

 pentagonal cardiac lobe. 



Length of carapace from base of rostrum = 11 mm. 



Affinities. — The form of the carapace, the conformation of the 

 rostrum, and the annular sulcus surrounding the median gastric 

 lobes distinguish this species. 



Distribution. — A single imperfect — but certainly recognizable — 

 specimen in the Woodwardian Museum, from the Coral Rag of 

 Upware, is the only evidence I have of the occurrence of this species 

 in England. It is found abundantly in the Upper White Jura of 

 Germany, where, as in England, it is associated with Prosopon 

 marginatum. In the specimen figured by Meyer (pi. x, fig. 4), the 

 rostrum is imperfect, and is wrongly represented as being short and 

 trifid. 



Genus Deoiiilites, Milne-Edwards. 



Deomilites Bijcklandi, Milne-Edwards. 



1858. BeU, Monogr. pt. i, p, 31 & pi. vi, figs. 1-11. 



Supplementary.^ — Bell has described this well-marked species in 

 detail. I have not been able completely to determine the characters 

 of the orbito-frontal border. Bell states that the rostrum is pointed, 

 but in the cast of the interior it is widely bifid. 



To this species it is exceptionally difficult to assign definite 

 characters which will apply to all stages of growth, so considerably 

 do they vary according to age. Bell's description applies accurately 

 to the earlier stages. Dr. Bucklandi may usually be recognized at 



1 The remarks made under this beading throughout are intended to supple- 

 ment the descriptions given by Bell in his Monograph on the Malacostracous 

 Crustacea (Palseont. Soc). 



