GENUS FIROLOIDA. 37 



compressed and almost three lobed, large, furnished with 

 broad curved and reticulated membranaceous margins, 

 when mature greatly enlarged beyond the calyx j external 

 integument closely adonaie, interior obsolete, charged with 

 the peculiar colouring matter of the root. (^* Style 0. stig. 

 mata 3." Jussieu.) deciduous, or obsolete in the membra- 

 naceous lobes of the fruit; perisperm farinaceous, almost 

 three lobed; corculumimmtv^^dy inverted, erect and flat; 

 radicle exserted through the perisperm; seed lobes ovate. 

 The seeds of i?. undulatum and R, compactum are so 

 very similar to those of the R, Rhaponticum that the same 

 description answers to the three, excepting that the seed 

 lobes of the two former appear a little more acute. 



From what we can discover then it appears that the 

 Eriogonum ought to be placed in the class Enneandria and 

 the order Trigynia of Linnseus instead o^ Monogynia where 

 it was placed by Michaux, by Persoon, and where it still 

 remains in Mr. Pursh's Flora of North America, and is 

 generically distinguished from Rheum as follows: 



Rheum. 



Enneandria trigynia. 



Calyx sexfidus, glabris, persistens Semen unicum 



triquetrum, alatum, njadum. 



Characters of a new GenuSf and descriptions of three new 

 Species upon which it is formed; discovered in the At- 

 lantic ocean^ in the months of March and April, 1816; 

 hat, 22' 9 . By C. A. Le Sueur,— Read April \5th, 

 1817. 



I now proceed to the description of a series of animals 

 heretofore unknown; they belong to the extensive family 

 of Pteropode moUusca; and may be arranged near to the 



