176 



Cincinnati Society of Natural History. 



the Cincinnati group at Cincinnati, Ohio, 150 to 175 ft. above low- 

 water mark in the Ohio River. 



STOMATOPORA TURGIDA, n. sp. 



Fig. S.—Stomatopora turgida, n. sp., and S. inflata, Ball, a, zoarium of 8. turgida, 

 growing upon Pachydictya spkndens, dr., natural size. b, same enlarged to Beven 

 diameters, showing the swollen zooecia and small apertures, c, small portion of the 

 zoarium of the turgid Cincinnati variety of S. inflata, Ball, also magnified seven 

 diameters. Introduced for comparison with S. turgida. 



Zoarium adnate, consisting of a single branching series of zocecia. 

 Zooecia comparatively very large, the anterior half much swollen, 

 rapidly tapering posteriorly with the slender, tubular proximal 

 end inserted beneath the turgid anterior end of the preceding 

 zocecium. Five zocecia, in five mm.; length of each zocecium 

 varying from 0.85 to 1.30 mm.; the greatest diameter of the ante- 

 rior half from 0.4 to 0.6 mm. The longest cells are the least tur- 

 gid, while the shortest are the most. Apertures round, bordered 

 by an elevated margin, small, o. 1 mm. in diameter, and situated 

 about one-fourth of the length of a zocecium from its anterior end. 



I have a number of specimens of this species, and all consist of 

 comparatively few zocecia. Nor do the series of cells in any of 

 them branch often, from which it appears that the production of 

 two "gems" was a much less frequent occurrence than in the 

 related S. inflata, Hall. (See Fig. 3, c.) S. turgida is further dis- 

 tinguished from that and all other species of the genus known to 

 me, by the much larger zocecia. 



Position and locality : Upper beds of the Cincinnati group at 

 Wilmington, 111. 



