236 



Cincinnati Society of Natural History. 



levels, one above the other, and it can not be said that the fronds are 

 ever divided into dissimilar axial and peripheral regions. 



Dr. Nicholson, in his description of this species, under the name of 

 Monticulipora (Peronopora) molesta (see syn. above), fails to recog- 

 nize several important characters, and besides gives an incorrect meas- 

 urement. He gives the diameter of the cells as from -g^th to -j^th inch. 

 I have not seen any specimen of this species in which the ordinary 

 cells had a greater diameter than y^-Q-th of an inch, nor do the cells in his 

 tangential section, as figured by him. appear to have had a greater di- 

 ameter. At any rate, it is certain that the cells in that figure are not 

 so large as those figured of some other species, which, according to 

 the measurements given b} T him, ought to be smaller. He did not 

 recognize the nature of the interstitial (?) tubes, but regards them 

 as true interstitial tubes, and of the same nature as in Peronopora 

 decipiens, Rominger, and Heterotrypa frondosa, D'Orb. ; but as I have 

 above stated, this is not their true nature. His tangential section 

 cuts the tubes transversely through the 2d phase mentioned by me 

 in nry description of the tangential section of this species, and be- 

 cause it shows a rather large number of the intercalated small tubes, I 

 believe that it was prepared from one of the frondescent examples, tan- 

 gential sections of which alwaj-s present a greater number of the small 

 tubes than do transverse sections of the massive specimens. This 

 I consider due to the fact that in the frondescent forms the di- 

 vergence of the tubes is much greater than in the massive examples, 

 making it necessary that young cells be more numerousl}' and rapidly 

 developed in the former than in the latter. 



I would suo-aest and recommend that Nicholson's name molesta be 



Bo 



retained as a varietal designation for the frondescent examples of this 

 species, as some title, by means of which it may be distinguished from 

 the massive and lobate examples, is, if not really necessaiy, at least 

 desirable. 



Formation and localitj': Cincinnati Group. The massive and lobate 

 variety can not be called common at any horizon or localit}^. The 

 best localities known, to me are on the hills south and west of Coving- 

 ton, Ky.; at an elevation of about 300 feet above low water mark in the 

 Ohio river. The var. molesta becomes a common fossil in strata from 

 75 to 100 feet higher in the series. The species appears to be confined 

 to these limits. 



Monticulipora l^evis, n. sp. (Plate X., figs. 1-15.) 

 Zoarium free, and forming small, sub-globular or irregular masses; 



