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INVERTEBRATE PALAEONTOLOGY. ;-{ 



they remark that it is very similar to some Sertulariidee, and even more like 

 certain types of Polyzoa. 



In regard to the geological range of this genus, we only know that the 

 typical species was found in the Eocene Tertiary of England ; while the form 

 here provisionally referred to it occurs in the Upper Cretaceous. 



Websteria cretacea. Meek. 



Plate 28, figs. 3, a, b, c. 

 Websteria cretacea, Meek (1864), Sniithsouiau Check-List Cret. Fossils N. Am., 2. 



The specimens of this curious fossil in the collection do not give a very 

 clear idea of its mode of branching; indeed, I was for some time inclined to 

 think it entirely simple. In a few instances, however, fragments of it have 

 been seen that bifurcate once ; and as none of those yet observed are more 

 than 0.66 of an inch in length, I have been unable to determine whether or 

 not it bifurcates more than once, though it probably does. 



Each of the numerous fragments yet seen measures uniformly about 

 0.03 inch in breadth. They are flattened or compressed, and provided with 

 a central axis, the diameter of which is about one-third the breadth of the 

 branches. In many instances there is along the middle of the stems and 

 branches, instead of the raised thread-like axis, a groove, as though the fossil 

 had split through the center in breaking the matrix, leaving, in one part, the 

 axis, and, in the other, a corresponding groove. This appearance, however, 

 may be deceptive, as I have never been able to see more than one side of the 

 same individual, and consequently do not know whether there is not always 

 -n raised axis on one side, and a corresponding groove on the other. 



The cellules are small, directly opposite, and occupy serratures i - egu- 

 larly disposed in the lateral margins, at intervals about equal to the breadth 

 of the branches, exactly as in many graptolites. A little below where the 

 stems bifurcate, they become slightly broader, and gradually develop two axes, 

 which diverge to the point of bifurcation, where they .separate, one following 

 along the center of each of the branches, which diverge at an acute angle. 



It is with some doubts that this fossil is here referred to the above 

 Eocene genus, but it seems to present, so far as known, no very important 

 characters by which it can be distinguished. Specifically, it differs from 

 W. crisioides of Edwards and Haime (Fos. Corals London Clay, p. 42, pi. 7, 



