New Lower Silurian Bryozoa. 



183 



in the collection and determination of the Silurian fossils of Minne- 

 sota, and to whom I am indebted for many favors. 



Position and locality; Upper part of the Trenton Shales, at St. 

 Paul, Minn., where they were collected by the author. 



RHINIDICTYA MINIMA, n. Sp. 



Fig. S.—Rhinidictya minima, n. sp. a, three fragments of the natural size ; b, one of 

 them x9; c, portion of same xl8, to show narrow zocecial apertures and surface orna- 

 mentation more clearly. 



Zoarium bifoliate, small; branches about 1.0 mm. wide, bifur- 

 cating at intervals of from 2 to 3 mm. Zocecia in five or six alter- 

 nating longitudinal rows between the bifurcations where the 

 branches have parallel margins. Apertures narrow, elliptical, 

 small, o. 11 mm. long, about half as wide, with sixteen in 5 mm. 

 longitudinally; margin of apertures thin and slightly elevated; 

 interspaces unusually wide, sometimes appearing flexuously striate, 

 usually with a distinct, granose, longitudinal line between the rows 

 of zocecia and one or two short ones in the slightly depressed 

 spaces between the ends of the zocecial apertures. Margin of 

 branches acute, the noncelluliferous band rather wide and occupied 

 by one or more lines of granules. 



This pretty little sptcies is easily recognized by its widely sepa- 

 rated narrow zocecial apertures, and the granulo-striate character 

 of the interspaces. Its branches also divide with unusual frequency. 



Position and locality: Top of Trenton Shales, at Cannon Falls, 

 Minn., where it is associated with numerous other small Brvozoa. 



