DECAPODA. 27 



ones in form or proportion, and does not extend beyond the internal 

 canthus of the ocular fossulae; those of the intermediate antennae are 

 prolonged in a direction rather parallel to the breadth of the shell 

 than to its length. 



There are some of them C. ll-dentalus. Fab., in which the ex- 

 tremity of the fingers are excavated like the bowl of a spoon: they 

 form the Clorodins, Leach. Several species, where they terminate 

 in a point, are remarkable for the arcuation of the edges of the shell 

 which terminate posteriorly by a fold and overlapping projection, 

 in the manner of an angle.. Those with a tridentated front, and 

 whose shell only presents that projection or posterior tooth, com- 

 pose his genus CarpWus. The species of this subdivision, C. co- 

 rallmus, F. ; C. mauculatus, Id., are marked with round blood- 

 coloured spots. They more particularly inhabit the Indian Ocean. 

 Many fossil Crabs appear to me to belong to this subdivision. 



The Xantho, of the same, some of which, Xanth. Jloridus, Leach, 

 Malac. Brit., XI; Cancer poressa, Oliv., Zool. Adriat., II, 3, inhabit 

 the coast of France, have their antennae inserted in the internal can- 

 thus of the ocular fossulae, and not in the outer one, as in those just 

 mentioned. 



Other considerations would authorise us to augment the number 

 of these divisions, but our limits require us merely to indicate the 

 principal ones. 



The " Crabe vulgaire de nos cules" of the first edition of this work, 

 has in this one been placed among the Portuni. P. masnas. 



Pirimela, Leach. 



These Crustacea completely i*esemble Crabs, but their external 

 antennae extend considerably beyond the front, and their stem, longer 

 than their pedicle, consists of numerous joints. The fossulae of the 

 intermediaries, as in the C. pagurus, are rather longitudinal than 

 transversal. 



But a single species is known, the P. denticulata, Leach, 

 Malac. Brit., VIII; it is found in the British channel and in the 

 Mediterranean. Perhaps we should refer to this species, the 

 fossil described by Desmarest under the name of Alelecycle ru- 

 gueux, in the Hist. Nat. de Crust. Foss., IX, 9. 



Atelecyclus, Leach(l). 

 Fossulae of the intermediate antennae longitudinal; lateral antennae 



(1) We had, at first, placed this subgenus, as well as the following one, among 

 the Orbicularia. 



