192 'Wisconsin Academy of Sciences^ Arts and Letters. 



formed by the grouping in various ways of beautifuily trilobate 

 semi-circular walls, after the manner of the fancy designs known 

 by the ladies as shell-work. The appearance of the surface is 

 more suggestive of modern Bryozoans than any other form. I 

 should judge that it belongs to the genus Alveolites. Another 

 well marked but undescribed fossil is doubtless a Fistulipora. 

 The manner of growth of this form is various. It sometimes 

 appears as an incrusting coral, sometimes grows out into thin 

 fronds, again is found in irregularly-lobed masses, and occasion- 

 ally takes the form of solid cylindrical branches. Its compara- 

 tively large cells, 6 to 8 in the space of a line, are elliptical in 

 outline and have prominent thin walls. These cells are irregu- 

 larly scattered over the surface, sometimes in contact but oftener 

 separated by interspaces which are studded with smaller circular 

 or polygonal cellules. These are of very unequal size and seem 

 to have no systematic arrangement. The sharpness of outline 

 possessed by cells and cellules in this form makes it one of the 

 handsomest of these little curiosities. 



From the facts observed during my examinations of these 

 fossils, and especially from that portion which has been herein 

 presented, the following conclusions have been drawn : 



1. Throughout the whole series here represented we find no 

 strongly marked lines of separation, but rather a group of forms 

 bound together by many points of similarity. 



2. These relationships preclude the possibilitj^ that we have 

 here the representatives of two sub-kingdoms. 



3. The close relationship borne by some of these corals to forms 

 distinctly radiate would seem to indicate that they hold an inter- 

 mediate position between the radiate and molluscan sub-king- 

 doms. It would be a hopeless task to attempt to establish their 

 exact relationships from these fragmentary skeletons. 



4. The extreme variability exhibited by the fossils themselves 

 precludes the existence of well-defined genera and species, and 

 points out an error in the past whereby these arbitrary distinc- 

 tions have been unnecessarily multiplied. 



5. The most careful study of extended collections is necessary 

 to enable the observer to fix the few distinguishing lines by which 



