EARLY PALEOZOIC BRYOZOA OF THE BALTIC PROVINCES. 



173 



PSEUDOHORNERA BIFIDA (Eichwald). 



Plate 8, fig. 5; plate 12; text figs. 88, 89, 90. 



Thamnisms hifidus Eichwald, Lethsea Rossica, vol. 1, 1860, p. 386, pi. 23, fig. 

 17 a, h. 



Eichwald's figures of this species, shown in text figure 88, are 

 scarcely enough to make its identification certain, but the fact 

 that he records his type-specimens 

 from Erras, Esthonia, and tha"" he 

 compares the species with Hall's Rete- 

 'pora (now Pseudohornera) diff , led 

 me to regard my conception of the 

 form as correct. From the various fig- 

 ures given here in the text and on the 

 plate, there should be little difficulty in 

 recognizing Pseudohornera hijida. Most 

 of the specimens are imbedded in the 

 rock and show only the noncel- 

 luhferous side, but one example was 

 found exhibiting the celluliferous sur- 

 face in a good state of preservation. 

 A view of this is presented on 

 plate 8. 



The rather regularly bifu^'cating branches, the fine, grano-lineate 

 ornamentation of the noncelluliferous side and the rather numerous 



Fig. 88.— Pseudohoeneea bifida. 



ElCHWALD'S VIEWS OF THAMNISCUS 



BirrDUs. a and 6, zoaeium, natural 



SIZE, SHOWING THE NONCELLULIFER- 

 OUS SIDE, AND PORTION OF THE SAME, 

 ENLARGED. "CALCAIRE 1 ORTHO- 

 CERATITES," EERAS, EsTHONIA. 





Wo; • /% o" 



ur 





-d^^io^^ 



Fig. 89.— Pseudohornera befida. a, tangential section, X20, of an old example showing thick- 

 walled, ANGULAR ZOCECLA; 6, VERTICAL SECTION, X20, EXHIBITING THE THICK, SOLID, NONPOEETEEOUS 

 SIDE PIERCED BY MINUTE TUBULI, AND THE SHAPE OF THE ZOCECIA; C, TEANSVEESE SECTION, X20. WAS- 

 SALEM BEDS (D3), UXNORM, ESTHONIA. 



rows of longitudinally arranged zooecia on the celluhferous face, are 

 characteristic of the species. 



Occurrence. — Eichwald records his types from the Ordovician at 

 Erras, Esthonia. Localities represented in the United States Na- 



