322 CUMA.DJ3. 



For the anatomical details I refer to the plates illus- 

 trating the paper. 



"During the summers of 1841 and 1842, I obtained a num- 

 ber of crustaceous animals, which I arranged promiscuously under 

 the genus Cuma of M. Edwards, it being my intention to publish 

 them at that time under this arrangement. I waited, however, 

 until it could be satisfactorily proved whether they were perfect 

 animals, or, according to the suspicions of M. Edwards, merely the 

 larvae of some Decapodous Crustacea. I have now satisfied 

 myself that they are perfect animals, and at the same time have 

 discovered the types of two new genera, which places the group 

 in a still more interesting point of view. 



(l I have applied the name Bodotria to one of these genera, and 

 Alauna to the other ; the former being the ancient name of the 

 Firth of Forth, at the mouth of which all these animals were got ; 

 and the latter, the ancient name of the river Forth. 



" The latter of these genera (Alauna) may be the genus Condy- 

 lurus of Latreille, as I have never seen that author's description ; 

 but whether it be so or not there cannot be any danger in applying 

 the name Alauna, as Condylurus had been previously used amongst 

 the Mammalia. 



" As I had a greater number of specimens of the Cuma Edwardsii 

 than of any of the others, I have been enabled to make out the 

 structure of that species with greater minuteness. 



*' These animals are very like small prawns in their general ap- 

 pearance ; but they bear perhaps in this respect a greater likeness 

 to the species of the genus Nebalia than to any other known Crus- 

 taceans. 



" The shell is hard and brittle, cracking under pressure. All the 

 species are of a pale straw colour. The thoracic portion of the 

 body is large and swollen ; it is composed of six segments ; the 

 abdomen is longer ; and is composed of seven segments. 



" M. Edwards, in his Memoir on the genus Cuma) published in 

 the 13th vol. of the Ann. des Sc. Nat., considers that the whole of 

 the first and largest segment of the body constitutes the head. In 





