BRYOZOA. 489 



cal lining on the inner side. The surface is more even, the cell 

 apertures are smaller, more rounded, the lunarium not so well 

 marked, the interspaces comparatively wider and slightly ele- 

 vated, so that they appear to slope down into the zooecial 

 apertures; of these about eight occur in three mm. The ooecia 

 are rather smaller, and the zocecial openings in the bottom, 

 eccentric in position. The ocecia, though also irregularly dis- 

 tributed, are less so than in S. foveolata. An arrangement in 

 transverse series is common. Interspaces minutely granular or 

 pitted. 



Position and locality: Keokuk group, Keokuk, Iowa, and 

 Warsaw. 111. The specimens from Warsaw are a little more 

 robust than those from Keokuk. Not rare. 



BUSKOPORA Ulrich, 188(5. 



(Contr. Am. PaL voL 1, No. 1, p. 22.) 

 (For generic diagnosis see page 383.) 



HrsKOPORA LUNATA Rominger. 



PI. XLVn, Fig. 7-7d. 



ii'itata Rominger. Proc. Acad. Nat. Sci. Phila., 1866. 



ta HalL Trans. Albany Institute, voL X. abstract, p. 10, 1881. 

 L-ii-kopora dentata Ulrich, 1886. Contri. Am. Pal., vol. I. p. 22, PL n, fig. 5-5a. 

 Lichenalia, lunata Hall. Rept. St. Geol. for 1885. Expl. to pi. 31, fig. 1-9, 1887. 

 Lichenalia lunata Hall, Pal. N. Y.. vol. VI, p. 77, PL 31, flgs. 1-9, 1887. 



A fine example lately obtained enables me to add some infor- 

 mation about this species. The example is evidently more 

 mature, its greatest thickness being about 4 mm., and shows 

 the fully developed characters at one point. Here the zooecia 

 apertures are much smaller than usual and the interspaces pro- 

 portionally wider. Upon close examination I find that this 

 peculiar appearance is due to a large portion of the original 

 aperature being covered by a thin membrane. The present ori- 

 fice occupies the space between the lunarium and the opposite 

 wall and is of oval or subcircular shape. The specimens being 

 silicified and entirely free from the matrix, it shows, where 

 fractured, the character of the interior. Fig. 7d represents a 

 portion of a vertical fracture and shows several zooecial tubes 

 61 



