BRYOZOA. 465 



their longer diameter, arranged in regular series, about seven 

 or eight in three mm. Mesopores shallow, developed in great 

 numbers, usually arranged in a single or double linear series, 

 between the sides of the zocecia, occasionally completely isolat- 

 ing a zocpriuin. In the fully matured perfect condition their 

 apertures are closed by a thin membrane. 



This very pretty species is distinguised by its small cells and 

 rather widely separated zooecia apertures. Their oval form and 

 the continuation of the peristome around the anterior margin 

 are also quite distinctive. 



Position and locality: Cincinnati group. Abundant at Cin- 

 cinnati, Ohio, especially at the foot of the hills. The same 

 species, or a closely allied form, occurs at Wilmington, 111. 



CKKAMOPORELLA STELLATA Ulrich. 



PI. XLI, flg. 1. la. 



Xoarium a thin subcireular crust upon foreign bodies. The 

 only specimen seen is 0.5 mm. in thickness, by about thirteen 

 mm. in diameter. Surface with prominent conical monticules, 

 their summits apparently solid, and about three mm. apart; 

 their sloping sides occupied by radially arranged zooecia. Zooe- 

 cia usually contiguous in the radial series, the series separated 

 by slightly concave furrows which diverge from the centre of 

 the monticules, and impart to the whole a stellate appearance. 

 Apertures very small, oval to subcircular, nearly direct, about 

 0.12 mm. in diameter, nine or ten in two mm. Hood or luna- 

 riuui very little developed except near the summits of the mon- 

 ticules. Mesopores very abundant, occupying the centers and 

 rays of the monticules, a few are found in the end spaces also. 



The conical monticules and the decided radial arrangement of 

 the zocecia are such striking features, that I do not hesitate in 

 pronouncing this a very distinct species. It cannot be con- 

 founded with any other known to me. 



Position and locality: Cincinnati group; Sterling, 111. 

 -58 



