BRYOZOA. 479 



the larger zoc^cia help in distinguishing it from the former, and 

 the different habit of growth from the latter. 



Position and locality: Hamilton group. Comparatively rare 

 at Buffalo, Iowa. 



FISTDLIPORA FOORDI Ulrich. 



PL XL VII, Fig. 7-7a, and PL XL VIII, Fig. 4-ia. 



Zoaiium a broad expansion; when complete, probably eight 

 to ten cm. wide; the only example seen is two and one-half 

 mm. thick at the edges, and five mm. in the thickest part. 

 Under surface \vith an epitheca marked by rather faint irregu- 

 larly concentric wrinkles. Large solid macula?, nearly on a level 

 with the surface, occur at intervals of six to eight mm., measur- 

 ing from center to center. Apertures immediately surrounding 

 the maculae, larger and more prominent than the others, de- 

 creasing gradually in size toward the middle of the inter-macu- 

 lar spaces, from 0.2 to 0.4 mm. in diameter, arranged in regu- 

 lar intersecting series, sub-triangular or pyriform in shape. 

 Lunarium very prominent, usually giving the apertures a 

 decidedly oblique appearance. When the apertures are closed by 

 opercular covers, the zoarial surface seems studded with triangu- 

 lar points, a little more than the diameter of their base apart; 

 about ten in 5 mm. Interspaces in general slightly concave, 

 but exhibiting irregular, faintly convex spaces, which are most 

 distinct on the surface of the maculae. Zocecial tubes a little 

 oblique to the surface, with diaphragms somewhat more than 

 their own diameter apart. The two ends of the lunarium pro- 

 ject strongly into the broadly pyriform zooecia. Vesicles large, 

 angular, irregular in shape, forming but a single series between 

 the zocecia, less shallow (in vertical section) than usual; the 

 macula? are entirely made up of them. Tangential sections 

 show that the interspaces are really of less width than the 

 zocecia. 



The present species is, perhaps, nearer related to F. astrica 

 Ulr., also from the Hamilton group, than to any other species 

 known to me. The points of dissimilarity between them are, 

 however, quite marked, and it is scarcely possible that they will 

 be confounded. 



Position and locality: Hamilton group, Rockford, Iowa. 



