SECONDARY AND TERTIARY FORMATIONS OF NORTH AMERICA. 125 



observed, although they may exist, since the specimens, like most of those from this 

 locality, are covered by a very delicate calcareous incrustation. 

 Only observed heretofore at Timber Creek, N. J. Cretaceous. 



» 



The figures given in Journal of Academy of Natural Sciences, will convey a very 

 good idea of the species, except fig. 23, which would make it appear that the colony 

 consisted of more than one layer. This is not so. The colony in this case is encrust, 

 ing another of a different species, which does possess several layers. There is another 

 point in the figure which is slightly incorrect. Three of the cellules are somewhat 

 too short. They vary a little in length, but not to the extent there indicated. 



It sometimes occurs that the crest or most convex portion of the cellule is abraded, 

 so as to present an appearance of a foramen below the mouth. This was observed in 

 a number of instances. Besides these characters, it may prove to be the case that a 

 row of small pores will be found at the extreme edge of the cellule, indicating the line 

 of separation. We are not able, from the material now before us, to decide positively . 

 on this point, but there are some appearances which render this probable. The pro- 

 minent surface of the cellule behind the mouth, and the very constant ovarian vesicle, 

 induced us to call this species bilabiata, but since this name has been used by Busk, 

 we propose to substitute the name of prolifica. 



C. exserta, n. s., fig. 6. — Colony generally small and radiating, encrusting shells 

 and other polyzoa. Cellules without any marked quincuncial arrangement, oval, very 

 prominent, presenting the appearance of being attached by only a portion of their 

 base, mouth terminal, large, round or transversely oval, pointing upwards and for- 

 wards, without any thickening or lip, but with the cellule slightly contracted around 

 it so as to look somewhat barrel-shaped. No special markings on the surface. 



This peculiar species can be at once distinguished by the exsert, irregularly placed 

 cellules, giving to the colony, even to the naked eye, an unusually rough appearance. 



We observed, in one instance, an appearance of an expansion or retroversion out- 

 wards of the lip ; whether this is the normal condition of the mouth, or merely ac- 

 cidental, we are unable to decide, since we could not find it again in a number of 

 colonies. 



The colonies are generally small, showing but thirty or forty cellules, but we have 

 a colony composed of cellules unusually small, amounting to perhaps over a hundred 

 in number. 



Not uncommon in the light grey marl of the Cretaceous, from near Mullica Hill. 

 We have a very much worn colony encrusting an oyster from near Yazoo, Miss., which 

 may prove to belong to this species, but there are no cellules well enough preserved to 

 identify them certainly. 



G. carinala G. and H. is a JReptoporina, q. v. 



For remarks on Cellepora typica, see under Eschari/ora. 



