BRYOZOA. 487 



and a thin irregular elevated margin. When perfect they ap- 

 pear as laterally perforated, prominent, round and smooth 

 tubercles, about 0.5 mm. in diameter. That they represent 

 ooecia will scarcely admit of doubt. The following three species 

 are all that are positively known to have this character, but 

 another form, of which my material is not good, most prob- 

 ably also belongs to the genus. 



STROTOPORA PERMINUTA Ulrich. 



PI. XL VII, fig. 4-4b. 



Zoarium having the form of small, irregular, hollow branches, 

 with a rugosely wrinkled epitheca on the inside; thickness of 

 zoarium 0.5 mm. or a little more. Surface with subsolid, 

 slightly elevated, conical monticules, about two mm. apart from 

 center to center. Slopes of monticules occupied by zooecia facing 

 outward from the center, so as to form radiating series. Aper- 

 tures suboval, but generally a little irregular in shape, 0.10 to 

 0.12 mm. in diameter, and eleven or twelve in three mm. Lun- 

 arium very prominent and overarching. Interspaces once and 

 a half to twice the width of the apertures. Ooecia comparativelv 

 small, about 0.4 mm. in diameter, with an eccentric opening at 

 the bottom; when perfect with a dome shaped covering in which 

 there is a lateral opening. They vary somewhat in number, on 

 different fragments, being numerous on some and few on others. 



The minuteness of the zooecia, the delicate zoarium, and the 

 dome-shaped oopcia, distinguish this species from all Fistuli- 

 poroid Bryozoa known to me from Devonian rocks. This spe- 

 cies is smaller in every respect than the Keokuk species next 

 described. 



Position and locality: Middle Devonian. Falls of the Ohio. 



STROTOPORA FOVEOLATA Ulrich. 



PL LXXVII, Fig. 9-9a. 



Zoarium having the form of solid compressed branches; four 

 or more cm. high, two or three cm. wide and four to eight mm. 

 thick. Surface with low, broad, rounded, generally transversely 

 elongated monticules. Inter-in onticular spaces less than the 



