American Palaeozoic Bryozoa. 



247 



can sa\% however, is, that I should never have believed it without being 

 able to study some better definition of Dianulites, than the utterly 

 worthless one given by the author of the name. I am totally averse 

 to the resurrection of old generic or specific names, of which the original 

 definitions are obscure, and consequently worthless, nor shall I 

 recognize any such restorations. But the redefinition of such long 

 current names as Favosites petropolitanus, Pander, Monticulipora 

 mammulata, and M. frondosa, D'Orbigny, I regard as entirely proper. 

 These cases are, however, in no way parallel, since the latter is a 

 benefit to the science; on the other hand, an attempt to restore an old, 

 ill\ r defined, and often quite forgotten name, does much to retard the 

 progress of knowledge, because it is always equivalent to adding a 

 source of much trouble and discussion. In this class of fossils it is 

 especially necessary to have the characters upon which a genus or 

 species is founded, clearly defined and figured, as it is quite impossible 

 to identify a species, with any degree of certainty, unless those re- 

 quirements are complied with. In whatever light other palaeon- 

 tologists may view this subject. I for one will not recognize any of the 

 recent publications (preliminary publications of work done for delayed 

 State surveys, etc., alone excepted), in which the names proposed are 

 not clearly defined, and the specific characters of the fossils figured. 



Formation and locality: Niagara Group. Rare at Osgood, Ind. 

 The small species of Monotrypa mentioned as being an associated 

 fossil, is common at that locality. 



Monotrypella ^equalis, now gen. et. sp. (Plate XL, figs. 3-3c/.) 

 Gen. char, ante p. 153. 



Zoarium somewhat irregularly ramose, the branches cyclindrical or 

 compressed, and form two to five tenths of an inch in diameter. Sur- 

 face often, smooth, usually however exhibiting low, rounded monti- 

 cules, which are occupied by clusters of large cells, the diameter of 

 which does not exceed -M:h of an inch. The ordinary cells are thin- 

 walled and polygonal in shape, with an average diameter of about 

 -^•th of an inch. Occasionally a few cell-apertures, having a slightly 

 smaller diameter than the ordinaiy cells, may be observed among the 

 large cells occupying the monticules. The latter are arranged at 

 distances apart of about .15 inch, measuring from center to center. 



In tangential sections (Plate XL, fig. 3) the tubes are regularly 

 pol}'gonal, with moderately thickened walls, and in contact with each 

 other on all sides. The line of demarcation between contiguous tubes 



