618 GEOLOGY. 



There was a close relation between several American and Russian 

 crinoids, implying intermigration. 



Almost the last of the trilobites. — The trilobites which commanded 

 our foremost interest at the opening of the Paleozoic are now almost 

 at the point of disappearance. The last-known genus is Phillipsia 

 (Fig. 286, I), a modest and beautiful form which retains the symmetry 

 of the ideal type and not a little of its elegance. The extravagances 

 of the Silurian and Devonian forms had vanished, and the last repre- 

 sentative of the family had the chaste beauty of its early ancestry. 



Other features. — Bryozoans were not uncommon, but the peculiar 

 devices for support illustrated in Archimedes and Lyropora of the pre- 

 ceding period were abandoned. The protozoans were represented 

 widely by a little foraminiferal shell, Fusulina secalicus (Fig. 286, p), 

 which had about the size and form of a grain of wheat. Their abun- 

 dance gives character to the " Fusulina beds" which occur in America, 

 Europe, and Asia. The corals were rare, as might be expected, under 

 the environmental conditions of the time. 



As already implied, the fauna had many cosmopolitan features, 

 not a few of its species being common to North America, Europe, 

 Asia, and Australia, and its general facies was the same in all these 

 regions. 



