220 SYSTEMATIC PALEONTOLOGY 



extremely small tubes which indicate that the reference of the fossil to 

 the Bryozoa may be incorrect. The upper surface shows extremely large 

 openings for a bryozoan, averaging 1 mm. in diameter, with thin walls. 

 In thin sections these cells are seen to be separated by small, irregular 

 mesopore-like structures. Vertical sections are particularly interesting 

 because here the rapid increase in diameter of the tubes from the minute 

 pores of the base to the wide openings of the outer part is well shown. 

 The walls in such sections are seen to be thin and slightly undulating. 

 No diaphragms are developed in either the larger or smaller tubes. 



It is possible that more extended study of this organism will show it to 

 be a coral related to Lichenaria, but most of the evidence at present seems 

 to indicate its relationship to the Bryozoa. 



Occurrence. CHAMBEESBURG LIMESTONE. This fossil and Nidulites 

 pyriformis are the two most abundant and characteristic species ot 

 the Nidulites bed of the Chambersburg formation. The comparatively 

 large tubes of this bryozoan may be seen in weathered cross-sections 

 wherever the more massive layers of the Nidulites beds are exposed. 

 Pinesburg and Wilson, Maryland, afford numerous specimens. 



Collections. Maryland Geological Survey, TJ. S. National Museum. 



Genus BATOSTOMA Ulrich 

 BATOSTOMA JAMESI Nicholson 



Plate LIV, Figs. 1, 2 



Chaetetes jamesi Nicholson, 1874, Quart. Jour. Geol. Soc. London, vol. xxx, 



p. 506, pi. xxix, figs. 10, lOb. 

 Chaetetes jamesi Nicholson, 1875, Pal. Ohio, vol. ii, p. 200, pi. xxi, figs. 



11, lla. 

 Monticulipora (Heterotrypa) jamesi Nicholson, 1881, Genus Monticulipora, 



p. 147, figs. 25, 26. 

 Batostoma jamesi Cumings, 1908, 32d Ann. Rep. Dep. Geol. Nat. Res. Indiana, 



p. 775, pi. vii, figs. 8, 8a; pi. viii, fig. 1; pi. xxvli, figs. 6, 6a. 



Description. Zoarium of small, rounded, solid stems marked at the 

 surface by large oval zocecia, rather conspicuous acanthopores and numer- 

 ous mesopores. In tangential sections the walls in the mature region 

 consist of thick, dark rings of dense tissue usually widely separated from 



