Sat/ on Shells, <f/-c. 387 



cessive partitions to the interior of the spire, as that part be- 

 comes too strait for the increasing volume of its body. If the 

 above supposition proves correct, the organs of communication 

 which pass through the oscuU, can hardly be in common, but 

 must rather connect the animals by simple contact only, other- 

 wise these parts would be broken when the animal changes its 

 place by vacating the inferior part of the tube. 



The third variety is then the state of that portion of the 

 tube which is inhabited by the body of the animal, and not yet 

 interrupted by the septse. 



From the above observations, it is evident that this species, 

 and probably the entire genus Favosite under which I have 

 placed it, will not arrange properly with the Tubipores, Mille- 

 pores, &c. but must be transferred to the Polypiers Lamelliferes 

 of Lamarck. And if the Madrepora retepora of Solander and 

 Ellis, is a true Pontes, as M. Lamarck supposes it to be from 

 the appearance of its tubes, I should conclude this genus to be 

 very proximately allied to Favosites, by that species and the 

 F. striata having in common the remarkable character of 

 fenestrated paries. But to this character I should conceive a 

 generic importance ought to be attached, as indicating a diflfer- 

 ential organization of the artificers. I have no doubt that on 

 close inspection of a perfect specimen, the same character 

 will be found to exist in F. Gothlandicum, and possibly also in 

 F. truncata. if not in the latter only, it may be proper to se- 

 parate the genus and to withdraw from Porites the foremen- 

 tioned species, retaining to striata as specifically essential, the 

 second member of the differential description. 



(To be continued.) 



