: BRYOZOA. 117 
Rhinidictya ] 
STOMATOPORA PROUTANA S. A, Miller. 
PLATE I, FIGS. 8-12. 
Stomatopora proutana S. A. MILLER, 1882. Jour. Cin. Soc. Nat. Hist., vol. v, p. 39. 
Ropalonaria pertenuis ULRICH, 1886. Fourteenth Ann. Rept. Geol. Nat. Hist. Sur. Minn., p. 59. 
Zoarium adnate, consisting of frequently branching, uniserially arranged zocecia. 
Zocecia slender, clavate, about 0.04 mm. in diameter at the proximal end, increasing 
gradually in size to from 0.12 to 0.15 mm. at the rounded anterior end ; each 0.6 to 
0.8 mm. long, with from eight to tenin 5mm. Aperture subterminal, small, circular, 
with a slightly elevated rim-like border; 0.05 to 0.06 mm. in diameter. 
The above describes the usual form of the species, but fig. 12 represents a 
variety occurring in the lower layers of the Trenton shales of Minnesota, and in the 
“Pierce” limestone of Tennessee, having unusually large zocecia. In this their 
length varies from 0.8 to 1.1 mm., while the diameter in the anterior third is gen- 
erally over 0.2 mm., and sometimes as much as 0.8 mm. 
In my preliminary report on the Minnesota Bryozoa this species was erroneously 
placed under the ctenostomatous genus Rhopalonaria. At the time I thought it 
advisable to extend the limits of that genus so as to include these delicate species 
of Stomatopora. Later studies have fully demonstrated the fallacy of such a view. 
Compared with American species, only S. tenwissima and S. inflata Hall, sp., will be 
found to exhibit any close relations. In the first the zocecia are more slender and 
longer; in the second they are much more inflated. S. elongata Vine, from the 
Wenlock of England, has slightly shorter zocecia of a form very nearly intermediate 
between those of S. proutana and S. inflata. 
Formation and locality.—This species occurs in the “‘ Pierce” limestone of Tennessee, the Birdseye 
limestone of central Kentucky, and the Trenton shales of Minnesota at Minneapolis, St. Paul and Cannon 
Falls; also at Decorah, Iowa. So far it has not been recognized in the Galena, but it is to be found, rather 
rarely though, in the Utica horizon at Cincinnati, Ohio, and more abundantly near the tops of the hills at 
that locality. It occurs also higher in the Hudscn River rocks at several localities in Ohio and Indiana, 
and at Wilmington, Illinois. 
Mus. Reg. Nos. 5926, 8066. 
STOMATOPORA INFLATA Hall. 
PLATE I, FIGS. 18-21. 
Alecto inflata HALL, 1847. Pal. N. Y., vol. i, p. 77. 
Hippothoa inflata NICHOLSON, 1875. Pal. Ohio, vol. ii, p. 268. 
Stomatopora inflata VINE, Nov., 1881. Quar. Jour. Geol. Soc. London. 
Zocecia resembling those of Hippothoa, short and wide when compared with the 
preceding species, pyriform, the proximal end contracted and springing from the 
under side of the anterior end of the cell beneath ; eight ornine in5 mm. Apertures 
