REPORT ON THE CRUSTACEA MACRURA. 117 



Archasastacus ivttlemccsii, 1 the name by which I propose to call this fossil specimen 



Fig. 29. — Archceastacus willemcesii, Sp. B., from the Lias of Lyme Regis. 



has the dorsal surface of the carapace almost circular. The anterior or frontal margin 

 being nearly straight between the orbital notches, while beyond them the lateral angles 



1 Brit. Assoc. Report, 1883 ; Geol. Mag., dec. hi., vol. i. p. 307, pi. x., 1884. Beneath the plate in the Geological 



