﻿April, 1857.] 



ELLIOTT SOCIETY* 



215 



observed in Europe or elsewhere. In Charleston, the following 

 genera are peculiar: Corynitis, Depurena, Eutima, Eucheilota, 

 and Persa. The genera, so far known only in America, therefore 

 may be summed up as follows : 



American. 'European. 

 Acaulis, 1 



Hippocrene, 

 Nemopsis, 

 Corynitis, 

 Dipurena, 

 Staurophora, 

 Eutima, 

 Eucheilota, 

 Persa, 



\ With which maybe compared - 



Bougamvillea, 

 Lizzia, 



Slabberia, 



Tima or Geryonopsis, 



Eucope, 



Circe. 



Without noticing further the characteristic genera of Europe, 

 these will serve to distinguish the continental types of the two 

 Faunas., 



Between the subdivisions of these continental types we find cli- 

 matic analogies, shown by the correspondence of certain generic, 

 or, at least, sub-generictypes, between the Faunas of those parts 

 belonging to the same isothermal zones. Tubularia and Sarsia are 

 the only genera found in both the Northern and Southern Faunas 

 of both the continents, unless further research should show that 

 this is the case with Obelia and Campanularia. But the Sarsia of 

 Boston Harbor is more analagous with those of Northern Europe, t 

 while that of Charleston Harbor is strikingly like that of the Medi- 

 terranean. The genus Tiaropsis is found on the Northern seas of 

 both continents, but is absent from the southern.* We find a simi- 

 lar analogy between the Tubularidee of the two continents, for there 

 is so strong a resemblance between the Tubularia described by 

 Kolliker from Messina, and the T. cristata of this paper, as to render 

 it difficult to separate them from mere written descriptions. 



We may, perhaps, take the isothermal of 50° Farh. as an approx- 

 imate boundary line between the northern and southern Faunas 

 of each of the two continents. This would divide the British Fauna 

 between the two zones, and there is actually a mingling of the 

 characters of the two Faunas in the Fauna of Great Britain. But 

 it is remarkable that of the four Sarsiae described by Forbes, the 

 three which have more or less long digestive trunks, and are, there- 

 fore, members of the same sub-genus as the S. mirabilis of Boston 

 Harbor, were like the last species found north of the isothermal of 

 50°; while S. prolifera, the only species agreeing with Gegen- 

 baur's 0. thelostyla and S. turricula, of this harbor, by the pres- 

 ence of a short digestive trunk is found just south of this isothermal 



