EARLY PALEOZOIC BEYOZOA OF THE BALTIC PROVINCES. 



153 



SCEPTROPORA FACULA Ulrich. 



Text fig. 74. 



Sceptroporafacula Ulrich, American Geologist, vol. 1, 1888, p. 228; Contr. Micro- 

 Pal. Cambro-Sil., pt. 2, 1889, p. 46, fig. 2; Geol. Surv. Illinois, vol. 8, 1890, 

 p. 401, fig. 15.— Whiteaves, Pal. Foss., vol. 3, pt. 2, 1895, p. 117.— Simpson, 

 Fourteenth Ann. Rep. State Geologist of New York for the year 1894, 1897, 

 p. 549, fig. 116. 



Rather numerous specimens of tMs interesting bryozoan occur 

 scattered through the fossihferous layers of the Borldiolm hmestone. 

 Here the species was first identified by a thin section whicli accident- 

 ally cut one of the segments. Further search in the rock awarded 

 well-preserved typical examples. Ulrich's description is copied below: 



Segments club-shaped, varying in length from less than 1 mm. to nearly 2 mm.; 

 lower half subcylindrical, about 0.23 mm. in diameter, noncelluliferous, covered with 

 fine, granulose, vertical strise; lower extremity bulbous, smooth; upper half cellulifer- 

 ous, expanding more or less rapidly, the depressed conical top varying in diameter 

 from 0.7 to 2 mm. The apertures of the zooecia on the top are subcircular; about 0.09 



Fig. 74.— Scepteopoea facula. a, single segment op Tms fine species, x18; 6, yektical section, 

 X18, through an entire segment; c, teansveese section, XIS, cutting the lowee end of a seg- 

 ment; d, TEANSVEESE SECTION, X18, THROUGH THE EXPANDED CELLULTFEEOUS POETION. RICHMOND 



GROUP, Stony Mountain, Manitoba. (After Ulrich.) 



mm. in diameter and arranged in radial series between raised lines about the large 

 central socket. As the zoarium expands the series increase in number by interpola- 

 tion. The apertures of the zooecia on the sides are ovate and a little larger, having an 

 average length of 0.11 mm. Like those on the top, they are arranged between elevated 

 granulose ridges. 



None of the arthrostyloid or other Paleozoic bryozoans approaches 

 this species in growth or other characters. The other Russian species 

 of the genus is quite different, as evidenced by a comparison of figures 

 74 and 75. 



Occurrence. — An abundant and highly characteristic fossil of the 

 Richmond group at Stony Mountain, Manitoba, the island of Anti- 

 costi, and other Canadian localities, and in the same strata at various 

 locahties in the United States, particularly at Wilmuigton and 

 Savannah, Illinois. Equally abundant in the Borkholm limestone 

 (F2) at Borkholm, Esthonia (Cat. No. 57248, U.S.N.M.). 



British Museum, one specimen from the Borkholm limestone at 

 Borkholm, Esthonia. 



