142 THE PALEONTOLOGY OF MINNESOTA. 



IPhyllodietya. 



PHYLLODICTYA FRONBOSA ?Ulrich. 



(Not figured,) 



Phyllodictya frondosa ULBICH, 1882. Jour. Gin. Soc. Nat. Hist., vol. v, p. 174, pi. 8, figs. 11. lla 



and lib. 



The name of this species occurs in the list appended to my preliminary report 

 on the Minnesota Bryozoa (Fourteenth Ann. Rep. Geol. Surv. Minn., p. 102; 1886). 

 The identification was based upon several small fragments, none of them in a con- 

 dition to afford satisfactory thin sections. Nor did any of the more numerous and 

 larger specimens of Phyllodictya collected subsequently for my own cabinet by Mr. 

 Charles Schuchert and others, as well as by myself, prove any better for that purpose. 

 I was, therefore, unable to verify the identification until last year, when I detected a 

 single well preserved fragment, about 15 mm. square, in a lot of fossils kindly given 

 me by Prof. C. W. Hall, of the State University. Both the superficial and internal 

 structure of this specimen, which was obtained too late to appear on the plates, 

 agrees closely enough with that of one of the original Kentucky types of the species. 

 Ordinarily, this would be quite sufficient to establish the identification of a species, 

 but in this case, a fact about to be mentioned causes me to use the question marks. 

 Recently I had occasion to prepare a set of thin sections of a specimen supposed to 

 belong to this species. These seem to differ so much from the original set, that one 

 of two things is evident : either I included two species in my original diagnosis of 

 P. frondosa, or the species is more variable in its internal structure than I supposed. 

 It is probable that the differences observed are only the result of age, but as I have 

 not had time to make the sections necessary to prove this, I thought it best to men- 

 tion the difficulty, leaving its removal to some future time. Before giving the fol- 

 lowing brief description of the Minnesota specimens, it would be well to mention 

 that the one received from Prof. Hall agrees best with the specimen represented by 

 fig. 11 of the original work on the species, while the resemblance to the specimen 

 that furnished the original thin sections and the enlarged surface view is much 

 less.* Also, that I now believe that none of the specimens catalogued by me in 1886 

 as P. frondosa really belong there. Most of them, perhaps all, are to be referred to 

 the new species P. varia. 



Zoarium leaf -like, 1.5mm. thick; size unknown, only fragments having been 

 seen. At intervals of 3 or 4 mm. the surface presents smooth or grano-striate 

 solid spots, 1 mm. or more in diameter. These spots may be on a level with the 

 general plane of the surface, or slightly depressed. Zooecial apertures ovate, a little 



*The new sot of sections were prepared from un example like thr firM. 



