418 SYSTEMATIC PALEONTOLOGY 



sive layers usually directly over each otlier so as to appear to form tabu- 

 lated tubes. At the surface the zooecia are irregular in shape and ar- 

 rangement, with the central and anterior portion more or less elevated 

 and the outline marked usually by two rows of small pores, one on each 

 of the adjoining zooecia. Mouths of pores direct and simple in 

 young expansions, but drawn out inwardly into short radially disposed 

 furrows in old specimens. Orifice anterior but not terminal, trans- 

 verse, semielliptical, but with the angles rounded. Border more or 

 less thickened and elevated, especially at the proximal margin just 

 behind which there is nearly always a peculiar, generally prominent, 

 avicularian cell. Further back, and near the middle of the proximal 

 half of the zooecium, is a well marked, usually semilunate pore. When 

 slightly worn, the orifice, avicularian cell and the semilunate pore form 

 a series of which the first usually is the largest, the second a little 

 smaller and the third the least. Measuring transversely about six 

 zooecia occur in 2.0 mm. ; lengthwise, four to five occur in the same 

 space. Gonoecia like the zooecia except that they have no avicularia 

 and in the place of the orifice have numerous small pores like those 

 around the border of the cells. 



This abundant and easily recogni^zed bryozoan probably is a close ally 

 of Cumuli'pora transylvanica (Eeuss) Manzoni,' though distinguished 

 readily enough by the larger si^e of its avicularian cell and in wanting 

 the row of pores within the marginal series that characterizes the Aus- 

 trian species. Another related species is the late Tertiary and recent 

 Alicroporella violacca (Johnston) Hincks. 



Concerning the generic position of the species we are not fully satis- 

 fied that it belongs to Adeonellopsis. Still this genus afl:ords a more 

 natural association for the species than it had in previous arrangements 

 and probably will serve as well as any other until the classification of 

 the Chilostomata is more settled. 



Occurrence. — ^Chesapeake Group. Petersburg, Va. (common). 

 Choptank Formation. Maryland (doubtfully identified). 



Collection. — U. S. National Museimi. 



iDenkschr. d. k. Akad. Wiss. Wien., Bd. xxxvii, Abth. ii, p. 53, Taf. ii, tig. 7, 1877. 



