EABLY PALEOZOIC BEYOZOA OP THE BALTIC PEOVINCES. 127 



is larger and coarser in every respect than any other species of the 

 genus. Its internal structure, however, is quite similar to that of 

 typical Graptodictya, so that there can be little question of its generic 

 placement. 



The type-specimen shown in figure 51 a lacks the characteristic 

 basal articulating point, but this undoubtedly was present and has 

 only been lost. 



Occurrence. — Apparently rare in the lower part of the Lyckholm 

 limestone (Fl) at Kurkiill, Esthonia. 



Eolotype.—Csit. No. 57220, U.S.N.M. 



British Museum, thin section of type-specimen. 



Family STICTOPORELLID^ Nickles and Bassler. 



This family differs from the Ptilodictyonidae mainly in that the 

 zoarium is not articulated, but grows upward from, and is continuous 

 with, a spreading base. 



Of the seven genera referred to the Stictoporellidse, only the type 

 genus Stictoporella is known at present in the lower Paleozoic rocks 

 of Russia. 



Genus STICTOPORELLA Ulrich. 



SUctoporella Ulrich, Journ. Cincinnati Soc. Nat. Hist., vol. 5, 1882, pp. 152, 

 169; Geol. Siu:v. Illinois, vol. 8, 1890, p. 394; Geol. and Nat. Hist. Surv. 

 Minnesota, vol. 3, pt. 1, 1893, p. 179; Zittel's Textbook of Paleontology 

 (Eng. ed.), 1896, p. 279. — Simpson, Fourteenth Ann. Rep. State Geologist 

 New York for the year 1894, 1897, p. 535. — Nickles and Bassler, Bull. 173, 

 U. S. Geol. Surv., 1900, p. 46. — Cumings, Thirty-second Ann. Rep. Dep. 

 Geol. Nat. Res. Indiana, 1907, p. 756. 



Micropora Eichwald, Bull. Soc. Nat. Mbscou, No. 4, 1855, p. 457; Lethsea 

 Rossica, vol. 1, 1860, p. 393. 



Not Micropora Gray, List of the specimens of British animals in the collection 

 of the British Museum, pt. 1, Centronise or Radiated Animals, 1848, pp. 

 115, 147. 



Zoarium branching, cribrose, or leafhke; zooecia with the primi- 

 tive portion tubular, usually long, generally without hemisepta, the 

 inferior one only occasionally present; orifices at the bottom of a 

 wide, sloping vestibule; thick-walled, untabulated mesopores occur 

 between the apertures and line the margins of the zoarium. 



Genotype. — Stictoporella interstincta Ulrich. = Ptilodicty a jlexuosa 

 James. Upper Ordovician (Eden) of the Ohio Valley. 



The diagnostic features of this genus, aside from its family char- 

 acters, are the long tubular primitive portion of the zocecium and 

 the presence of more or less numerous, untabulated, thick-walled 

 mesopores. Eichwald founded his new genus Micropora upon a 

 species which proves upon further investigation to be a Stictoporella. 

 However, the name Micropora was preoccupied by Gray for a genus 

 of chilostomatous bryozoans, so that Stictoporella remains a valid 

 name. 



