EAEL.Y PALEOZOIC BEYOZOA OF THE BALTIC PEOVIISrCES. 



135 





Genus PHYLLODICTYA Ulrieh. 



Phyllodictya Ulrich, Journ. Cincinnati Soc. Nat. Hist., vol. 5, 1882, p. 153. — Mil- 

 ler, North Amer. Geol. and Pal., 1889, p. 315. — Ulrich, Geol. Surv. Illi- 

 nois, vol. 8, 1890, p. 390; Geol. and Nat. Hist. Surv. Minnesota, vol. 3, 1893, 

 p. 141; Zittel's Textbook of Paleontology (Eng. ed.), 1896, p. 280.— Simpson, 

 Fourteenth Ann. Rep. State Geologist New York for the year 1894, 1897, p. 

 531.— NiCKLES and Bassler, Bull. 173, U. S. Geol. Siu:v., 1900, p. 49. 



The members of this genus differ from other Rliinidictyonidse 

 in having broad, bifoHate zoaria with long zooecial tubes crossed by 

 complete diaphragms 

 and without hemisepta. 

 Its relations are mainly 

 with Pachydidya, but 

 Phyllodictya has more or 

 less strongly oblique 

 apertures with the pos- 

 terior edge raised. Of 

 the two known Russian 

 species, one is identical 

 with an American form, 

 while the second is new. 



Genotype. — PJiyllo- 

 dictya frondosa Ulrich. 

 Middle Ordovician 

 (Black River) of the 

 United States and Can- 

 ada. 



PHYLLODICTYA FLABEL- 

 LARIS, new species. 



Plate 7, figs. 7, 8; text fig. 59. 



This fine new species 

 differs from all other 

 members of the genus 

 in the greater dimen- 

 sions of both the zoa- 

 rium and zooecia. The 

 zoarium is a broad bifoliate expansion of which figure 7 on plate 7 

 represents only a fragment. The original of this t5rpe-specimen must 

 have been at least 40 mm. in height and 60 mm. in width, with a 

 maximum thickness of 4 mm. Another specimen before me has a 

 still greater thickness, so that its other dimensions were probably 

 correspondingly larger. The surface of these zoaria is marked by 

 finely granular solid spots or maculas at intervals of about 5 mm. 

 The more perfect condition of the surface shows the zocecia to be 

 arranged in longitudinal series between faintly papillose ridges, but in 

 old examples this arrangement is much obscured. Four zooecia 





Fig. 59.— Phyllodictya flabellaris. a, vertical section, 



X20, SHOWING THE LONG, ZOCECIAL TUBES; 6, MINUTE STRUC- 

 TURE OF THE INTERZOCECIAL SPACES, XCO; C, TANGENTIAL SEC- 

 TION, X20, WITH PORTION OF A MACULA AND ADJOINING 



zocecia; d, several zocecia of the same section, X35. 

 Orthoceras limestone (B3), Baltischport, Esthonia. 



