190 Wisconsin Academy of Sciences, Arts and Letters. 



rather prominent, rounded tubercles with concave interspaces. 

 Cells polygonal, those on the tubercles not differing in shape or 

 size from the others ; ten to fourteen on the stem in the space of 

 one-eighth of a linear inch. The cell walls are sharp, without 

 intercellular pits or pores, but elevated at the angles so as to form 

 low points. This description is abridged from that given by that 

 eminent paleontologist on page 71, An. Eep't, before cited. 

 MonticuUpora rnuUituberculata is the formidable name borne by this 

 little fellow. If. rectangularis differs from this in the form and 

 arrangement of cells ; these are generally quadrangular, and are 

 arranged in concentrically curved lines showing much the same 

 arrangement as the engraved lines on the surface of a watch -case. 

 The third form is almost intermediate between these two types in 

 surface markings, but is of larger growth and has less prominent 

 monticules. The pores are quite generally hexagonal and are 

 arranged in straight or gently curving lines. This form is unde- 

 scribed. 



There is some doubt in my mind as to the existence of any 

 constant difference between these three forms. The concentric ar- 

 rangement of cells is sometimes observable at the ends of branches 

 of M. mulfiiuherculata, and M. rectangularis does not always dis- 

 play this arrangement of pores over the whole surface. The 

 elevated spiny angles which characterize the cell walls of the first 

 named species are not always apparent, and are sometimes to be 

 observed on the latter form. The undescribed form is too closely 

 allied to the others to warrant a separate description or designation. 

 The wide variation in form and features would seem to indicate 

 that at most only varieties should be claimed for these forms. 

 The genus Chcetetes to which the four succeeding species are as- 

 signed was originally thought to include forms like the last, but 

 its author described the increase of its cells as taking place by 

 division. In most of the forms in which the method of increase 

 of parts has been male out it has been found to be by a diff'erent 

 process, and so the new genera MonticuUpora stenopora, etc., 

 were founded, and into these genera were gathered those forms 

 that were found to disagree with the original genus in this respect. 

 The most that we can say of some of these is that they are at 



