NORTH AMERICAN EARLY TERTIARY BRYOZOA. 507 



elliptical in the interior, and surrounded by a score of areolae. The peristome is 

 complete, somewhat projecting and rather thick. The peristomice is oval and elon- 

 gated; the peristomie is shallow; it contains proximally a small pointed triangular 

 avicularium almost transverse, and distally the aperture, which in the interior is 

 semilunar with a slight convex proximal border. The stellate ascopore is placed 

 on the median part of the zooecia close to the peristome. One of the areolae is 

 transformed into a round, rather large, irregularly placed avicularium, giving to 

 the zooecia a strange and undefinable aspect. The gonoecia are larger than the 

 ordinary zooecia and bear three ascopores arranged in a triangle and placed in a 

 cavity of the frontal. 



Measurements. Apertura|Aa=0.07mm. . |Za= 0.40-0.44 mm. 



(interior) 1/^=0.08 mm. ia 1.7.3=0.16-0.20 mm. 



Height of peristomie=0.14-0.16mm. 



. f.?r/=0.40-0.50mm. 

 (jronoecia , 



(7zg=Q.30 mm. 



Variations. The variations are very numerous and the species is quite irregu- 

 lar, but only the pleurocyst is affected externally, for in the interior the zooecia 

 and the apertura are very constant in their form and their micrometric dimensions. 



The peristomial avicularia. which are salient and visible (figs. 16, 19). are 

 often more or less deeply imbedded and then become invisible (figs. 17. 18). 



The ascopore. more or less removed from the peristomice (figs. 16, 17). ap- 

 proaches it (fig. 18). and even rather frequently opens into the peristomie itself 

 (fig. 19). 



The species may have two adventitious avicularia on a zooecium (fig. 17). 

 which still more complicates the zooecial irregularities. Their occurrence appear 

 much less constant on the ovarian zooecia (fig. 12). 



In the interior (fig. 13) the ascopore is stellate and of rather variable form. 



In tangential section (fig. 14) it will be noted that the adventitious avicularia 

 result often from the coalescence of many areolae. Above many of the zooecia 

 there is a pore hardly visible exteriorly but which is much more constant in the 

 other species. The pleurocystal elements are rather large, scattered, without mani- 

 fest orientation. Finally, the line of juncture of the zooecia is finely undulating, a 

 feature which is very rare. The zooecial walls are very thick and the areolar 

 cavities are true pore-tubes. 



Affinities. This species differs from Adeonellopsis (Poricella) elongata Canu. 

 1907, from the French Lutetian, in its somewhat larger micrometric dimensions, 

 in its prominent adventitious avicularia. its ascopore smaller externally, and in the 

 proximal lip of the aperture, which is convex and not concave. It differs from 

 Adeonellopsis grandis in its very small zoarium and in the absence of a cribriform 

 area on the gonoecia. 



Occuwence. Claibornian (Gosport sand) : One mile southwest of Rockville, 

 Clarke County, Alabama (common). 



Lower Jacksonian (Moodys marl) : Jackson, Mississippi (rare). 



Cotypes.Cat, No. 63854, TJ.S.N.M. 



