BRYOZOA. UI 
Distribution.] 
with Worthenopora, belonging to the Chilostomata, are new types. Among the T'repo- 
stomata, the Fistuliporide are abundant, and Stenopora, Leioclema, Anisotrypa, and 
Batostomella not uncommon. Both the Cyclostomata and Ctenostomata are poorly 
represented, each by one or two insignificant species. 
CaRrBONIFEROUS System: The rocks of this age are mostly unfavorable for the 
preservation of the Bryozoa, and only a few localities are known in this country 
where good specimens may be obtained. With the exception of Stenopora and Fistu- 
lipora all the observed forms belong to the cryptostomatous genera Fenestella, 
Polypora, Thamniscus, Acanthocladia, Pinnatopora, Septopora, Diplopora, Sphragiopora, 
Chainodictyon, Prismopora, Cystodictya, and Rhombopora. 
In America Bryozoa are rare orentirely unknown in the strata above the paleo- 
zoic. ost of the species known are from the Cretaceous and Tertiary rocks of New 
Jersey, Mississippi and Arkansas. In Europe the Triassic system is equally poor in 
Bryozoa, but in the Jurassic they are represented by nearly eighty species, most of 
them Cyclostomata, This suborder continues to be almost exclusively represented to 
the Cenomanian in which the Chilostomata are present, though not yet in very great 
numbers. Even in the Upper Cretaceous, from which d’Orbigny mentions 662 species, 
the Cyclostomata and Trepostomata are nearly twice as numerous as the Chilostomata. 
In the Tertiary rocks the Cyclostomata have become less numerous and the Chil- 
ostomata more abundant, the ratio of representation at the close of the age being 
approximately like the present. 
