C HATTER THIRD. 



THE GENUS CYANEA AND ALLIED GENERA. 



SECTION I. 



GENERAL DESCRIPTION OF CYANEA ARCTICA. 



I HAVE never felt more cleej)ly the imperfection of our knowledge of some of 

 the most remarkable types of the animal kingdom, than in attempting to describe 

 the beautiful representative of the genus Cyanea found along the Atlantic coast 

 of North America. I can truly say that I have fully shared the surprise of casual 

 observers, in noticing this gigantic Radiate stranded upon our beaches, and won- 

 dered what may be the meaning of all the different parts hanging from the lower 

 surfixce of the large gelatinous disk. It is true that naturalists have long ago given 

 particular names to all of them, — they have distinguished a mouth, a stomach, 

 ovaries, tentacles, and even applied the name of eyes to some prominent specks on 

 the margin. But if the aim of our science is not, simply, to adopt arbitrary desig- 

 nations, by which we may describe animals, in such a manner as to distinguish 

 them with precision from any others, but to acquire an insight into their true 

 relations, the question at once arises, how far the names in use to designate the 

 different parts of the lower animals are justifiable, when they recall familiar organs 

 of well-known types, allied to man himself Is that which is called mouth, in 

 Jellyfishes, truly a mouth ? is the so-called stomach truly a stomach ? are the so- 

 called ovaries really ovaries? are their tentacles in any way comparable to those 

 of MoUusks and Worms? have the parts designated as arms any resemblance to the 

 upper limbs of the Vertebrates? In the present state of our knowledge of organic 

 structures, we must unconditionally answer, that there is only a remote analogy 

 between the parts designated under the same names in different types of the 

 animal kingdom, and that these names were adopted, in the infancy of our science. 



