48 



Species. 



154. S. botryoides With oblong, ovate lobules, apices 



hollow and open. 



155. radiciformis . ...With tortuous, dichotonrous 



branches, compressed at the 

 apex. 



156. prolifera Palmated, with frequent divisions, 



and distinct finger-formed pro- 

 cesses. 



157. ossiformis White, subramose; apex thick- 



ened and jagged. 



158. membranosa ....With cellular membranes, exter- 



nally muricated. 



159. fulva Amorphous and subramose. 



160. floribwida Confluent, with ramose fasciculi ; 



having a chaffy flosculent down, 

 and being obtuse and thicker at 

 the apex. 



161. baccillaris Erect, caulescent; with porous 



branches, applied to each other. 



The existence of fossil sponge in the transition or in the 

 mountain limestone has not been ascertained, or in the dif- 

 ferent beds of the lia formation ; but the tenuity, in ge- 

 neral, of its substance, and the nature of the matrices in 

 which it has been sought, may perhaps occasion its con- 

 cealment* Of its presence in the several oolitic beds, I 

 have not been able to acquire any satisfactory information, 

 except that in the Portland freestone I have seen semi- 

 sphaeroidal masses, about eighteen inches in diameter, di- 

 vided into flattish, foliaceous, laciniated, erect lobes, and 

 which appear to possess a spongeous structure. Specimens 

 are sometimes found in the green sand formation, but not so 

 frequently as may ' have been expected : the specimens 

 which are most frequently found, are, I suspect, those which 

 are adherent to the accompanying fossil shells. 



