EAEL.Y PALEOZOIC BRYOZOA OF THE BALTIC PEOVINCES. 171 



Obverse strongly convex, with three rather irregular rows of zooecia, their apertures 

 Bubcircular, with a distinct peristome, about 0.1 mm. in diameter, eight or nine in 

 2 mm. Acanthopores abundant, in-egularly distributed, rather large, especially so 

 in the earliest forms of the species. Interspaces slightly concave, occasionally faintly 

 pitted and striated. 



In tangential sections the zooecia are rather short, with a row on each side directed 

 obliquely outward, and one series between them. The latter are wedge-shaped, and 

 in deep sections appear as a more or less narrow central space. Diaphragms, one in 

 each tube, have been observed. 



Occurrence. — The American specimens are from the Black River 

 and early Trenton, at various localities in New York, Vermont, 



Fig. 86.— Chasmatopora reticulata. Ulrich's figures of Phylloporina reticulata, a aotj b, two fragments, 



NATURAL SIZE, EXPOSING THE REVERSE SIDE; C, PORTION OF 6, X9; d, PORTION OF a, X9, SHOWING BROADER BRANCHES; 

 e, CELLULIFEROUS SIDE OF A FRAGMENT, X18. BlACK RiVER (DECORAH) SHALES, MINNEAPOLIS, MINNESOTA. 



Minnesota, and Canada. Not uncommon in the Wassalem beds 

 (D3) atUxnorm, Esthonia (Cat. No. 57262, U.S.N.M.). 



Represented in the collections of the British Museum by specimens 

 from American localities. 



CHASMATOPORA FURCATA (Eichwald). 



Plate 12; text fig. 87. 



Polypora furcata Eichwald, Bull. Soc. Nat. Moscou, No. 1, 1854, p. 89; No. 4, 

 1855, p. 451; Lethsea Rossica, vol. 1, 1860, p. 378, pi. 23, fig. 11a, b. 



Eichwald' s figures of this species show its characters in sufficient 

 detail to cause its recognition easy. Its diagnostic features are, 

 firstj the large size of the fenestrules, and, second, the conspicuous 



92602°— Bull. 77—11 13 



