ANIMAL KINGDOM. 315 



Cirripeda to the radiated system of Asterias be conducted 

 in kny manner similar to this, it will then only be neces- 

 sary to investigate the nature of the chasm that so widely 

 separates them. 



I have only one tiling more to observe on this subject, 

 namely, that if the radiated disposition of the internal and 

 external parts of the genus Coronula forcibly reminds 

 us of the genus Echinus, and if Linnaeus describes it as 

 " testa Jigura Echini absque radiis" it ought moreover 

 to be recollected that the articulated feet of a Cirripede 

 are not absolutely invisible among the Radiata. It was 

 even upon this principle that M. Latreille detected their 

 affinity. " Les Comatules" says this naturalist, " et les 

 Euryales, genres de cette division classique (Radiaires), 

 nous montrent positivement des parties analogues aux bras 

 des Cirrhipedes, celles qu'on distingue sous le nom de 

 rayons articules, et quelquefois dichotomes tels que ceux 

 des Euryales. On en voit autour de la bouche dans les 

 Comatules" 



Radiata. 



The Echini deserve attention, as after them no Radiated 

 animal has two apertures to its intestinal canal ; they lead 

 immediately by means of the genus Scutella to the Stelle- 

 rides of Lamarck, a group which is the same with the 

 genus Asterias of Linnaeus. Those animals which com- 

 pose the modern genus Ophiurus make the passage very- 

 easy and gradual. from the true Starfish to Medusa Andro- 

 meda, and M.frondosa, which form part of the genus Cas- 

 siopea of Peron. This naturalist, who has contributed 

 more than all others together towards our acquaintance 

 with the nature of the Medusa, has so well described the 

 singularity of these animals, that I cannot do better than 



