CX PROCEEDINGS OF THE GEOLOGICAL SOCIETY. [May 1 896, 



from the Forest Marble of Malmesbury, Wiltshire, under the name of 

 Palceinachus longipes (Quart. Journ. Geol. Soc. vol. xxii. 1866, 

 pp. 493-4, pi. xxiv. fig. 1), which is still the oldest fossil crab 

 known. 



As the limbs are preserved, as well as the carapace, its deter- 

 mination is all the more satisfactory and reliable. The legs are 

 extremely long and slender ; in this respect, and also in their form 

 and in that of the carapace, with its remarkable prominent tubercles 

 in front, it closely resembles the common 4 Spider-Crabs ' — the 

 Maidae and Leptopodidae — living on our own coasts at the present 

 day, and the great Japanese Crab, Mecocheirus Kempferi, of De Haan. 

 In 1868, 1 figured and described the carapace of another Brachyuran 

 Crustacean, but without limbs attached, from the Great Oolite of 

 Stonesfield, under the name of Prosopon mammillatum The Upper 

 White Jura of Ulm, Germany, has yielded carapaces of several 

 minute Crustacea, which are either Brachyurous or Anomurous ; 

 these are generally placed under the Dromiacea, but unfortunately 

 no limbs or abdominal segments have been found associated with 

 them. As many as 3 genera and 26 species of these forms 

 have been figured and described by H. von Meyer, Quenstedt, 

 and B-euss. 



Although short-tailed or Anomalous Crabs are rare in the 

 Jurassic Series, they become more abundant in Cretaceous times, 

 and we find not only the earliest and simplest forms, such as 

 Dromiacea, but also representatives of all the great families of the 

 Brachyura. 



Commencing with the Dromiacea, we find a genus, like Dromilites, 

 which I have named Prosopon Etheridgei, occurring in the Cretaceous 

 of Queensland, Australia ; CypJionotus incertus and Plagiophihalmus 

 oviformis, from the Green sand of Cambridge and of Wiltshire ; 

 Diaulax Carteriana, from the Cambridge Greensand, and D. feliceps, 

 from the Gault, Folkestone ; Platypodia Oweni, from the Chalk of 

 Sussex ; Polycnemidium pustulosum, from the Chalk of Bohemia ; 

 Glyph rthy reus formosus, from the Planer-Kalk of Ebendort ; Dro^ 

 miopsis rugosa, from the Chalk of Faxoe ; and Homolopsis Edwardsi, 

 from the Gault and Greensand of England. 



Dromilites Lamarckii, of Desmarest, and Ooniocliele angulata, of 

 Bell, are both London Clay forms from the Isle of Sheppey ; Steno- 

 dromia is from the Eocene, Biarritz. These complete the Tertiarj 7 ; 

 record, while about 9 genera and numerous species are widely 

 distributed over the seas of the world and are still living. 



