from a living Individual taken off Guernsey. 46 1 



from equatorial regions, except one discovered in the year 

 1815 by M. Risso, and described by him (although imper- 

 fectly), which he named Chrysoma mediterranea; and he 

 regards himself as the founder of this new genus. It was 

 discovered near the coast of Nice. This species is figured by 

 Guerin, in his Memoire sur V Organisation Exterieure des Phyl- 

 losomes," as P. mediterraneum. 



My specimen lived but a short time after its capture, and 

 appeared, when walking, as shown in b. Guerin, in his Me- 

 moire, has figured twelve species : in all of them the flagelli- 

 form process is feathered at the last joint; this was but slightly 

 the case with the one now described, and was only observable 

 during life. This individual appears intermediate between P. 

 ReynandzV and P. mediterraneum. The horn-like antennae ap- 

 proach those of the ReynandzY; but the interior pair have the 

 outer terminating article longer than the internal one, which 

 is the reverse of the condition in the ReynandzV : the descrip- 

 tion of that species agrees with my animal in other respects. 

 In the P. mediterraneum, the peduncles of the eyes are much 

 longer ; the inflated margin of the carapace is wanting, and its 

 form differs in being more regularly oblate than in mine. 



The two spines bent downwards just below the mouth, at 

 the commencement of the thorax, and the spines above the 

 insertion of each leg, appear to supply a distinct character 

 in this species. 



All that is known of the habits of this singular genus is, 

 that the animals are found on the surface of the water, and 

 swim slowly, in which operation they move their flagelliform 

 processes. This is nearly all that has been observed hitherto ; 

 and, as my individual came up in a bucket in deep water, it is 

 probable that the species delights near the surface in calm 

 weather, and sinks into the deep when the sea is ruffled. 



The following are the names, and some particulars on the 

 forms which have been discovered : — 



Chrysoma mediterranea Risso, 1815. 

 12. liinifrons Latreille Coast of Coromandel. 



