EAKLY PALEOZOIC BKYOZOA OF THE BALTIC PROVINCES. 347 



the figure here introduced, little can be said about the species except 

 that it is a massive bryozoan, apparently. Before the species can be 

 considered valid, the internal structure of the type must be described 

 and figured. 



Occurrence. — Hohenholm, island of Dago, probably in the Lyck- 

 holm limestone. 



Genus PTEROPORA Eich-wald. 



Pteropora Eichwald, Lethsea Rossica, vol. 1, 1860, p. 395. 

 According to Eichwald, this genus is related to IcJitliyoracMs McCoy, 

 but differs in having a celluliferous tissue 

 connecting the lateral branches. It is 

 in this very character that the genus is 

 peculiar and unlike any other fenestellid or 

 similar bryozoan. Eichwald possessed only 

 a single specimen of each of his species, and 

 as these were attached to the rock he did 

 not determine the nature of the opposite face. 

 None of the specimens in the various collec- 

 tions I have studied has shown the characters ascribed to Pteropora. 



PTEROPORA PENNULA Eichwald. 



Text fig. 223. 



Pteropora pennula Eichwald, Letliaea Rossica, vol. 1, 1860, p. 396, pi. 23, figs. 

 15a, b. 



As remarked above, I have been unable to identify this species, 

 and, in accordance with my plan of including 

 identified species only in the main body of 

 this paper, this and the following form must 

 remain uncertain. 



Occurrence. — ''Calcaire a Ortheratites," 

 Spitham, Esthonia. 



PTEROPORA EXILIS Eichwald. 



Text fig. 224. 



Pteropora exilis Eichwald, Letheea Rossica, vol. 1, 

 1860, p. 397. 



Fig. 223.— Pteropoea pennula. 



a AND b, ElCHWALD'S VIEWS OF 

 THE TYPE-SPEQMEN, NATUEAL 

 SIZE AND ENLARGED. ORDOVI- 



ciAN, Spitham, Esthonia. 



Fig. 224.— Pteropora exilis. a 

 and 6, zoarium natueal size, 

 enlarged. Ordovician, Er- 



EAS, ESTHONIA. (AFTEE EICH- 

 WALD.) 



All that is known of this species is shown in the accompanying figure. 

 Occurrence. — ''Calcaire a Orthoceratites, " Erras, Esthonia. 



PTELOPORA DISTICHA Goldftiss. 



Glauconome disticha Goldfuss, Petref. Germ., vol. 1, 1827, p. 217, pi. 64, fig. 15. 

 Ptilopora disticha Eichwald, Lethsea Rossica, vol. 1, 1860, p. 383. 



Under the above name Eichwald identified a species supposed to be 

 the same as the widespread Silurian form now known as Pennirete- 

 92602°— Bull. 77—11 24 



