232 BULLETIN 7*7, UNITED STATES NATIOITAL, MUSEUM. 



distinguish the present form. Massive bryozoans of other genera 

 in the Russian Ordovician lack the vitreous substance and rough 

 fracture of D.fastigiatus, and therefore will not be confused. 



Occurrence. — The specimens in the collections of the United States 

 National Museum were derived from the Echinospherites limestone 

 (Cl) at Duboviki, on the Wolchow River, Katlino and Gastilizy, 

 and in the Glauconite limestone (B2) at Pulkowa and Pawlovsk in 

 the government of St. Petersburg, and from the Chasmops limestone, 

 south of Bodahamn, island of Oeland, Sweden. The additional 

 locahties, Erras, Reval, and Baltischport, are recorded by Dybowski. 



Plesiotypes.—Csit. Nos. 57334 to 57338, U.S.N .M. 



Thin sections of the figured specimen from Duboviki, and speci- 

 mens from the Chasmops limestone, Oeland, are in the collections 

 of the British Museum. 



DIANULITES PETROPOLITANA Dybowski. 

 Plate 2, figs. 4^6a; plate 10, figs. 7-11; text figs. 129-132. 



Dianulites petropolitana Dybowski, Die Chaetetiden der Ostbaltischen Silur- 



Formation, 1877, p. 24, pi. 1, figs. 4 and 5. 

 Hexaporites Pander, Beitr. zur Geogn. d. russ. Reiches., 1830, p. 106, pi. 1, fig. 



5; pi. 28, fig. 8. 

 Hexaporites fungiformis. Lexjchtenberg in Eichwald Geognosie de Russ., 1846, 



p. 370. — Eichwald, Lethsea Rossica, vol. 1, 1860, p. 478. 

 Dianulites petropolitanus var. hexaporites Dybowski, Die Chaetetiden der Ost- 



baltischen Silur-Formation, 1877, p. 30, pi. 1, figs. 6, 6a. 

 Monotrypa (Chsetetesf) cumulata Ulrich, Geol. and Nat. Hist. Surv. Minnesota, 



vol. 3, pt. 1, 1893, p. 307, pi. 27, figs. 26, 27. 



The following may be included, at least in part, in the present 

 species : 



Millepora hemispherica (part) Eichwald, Inter ingrica et de trilob. observat., 

 1825, p. 21. 



Favosites petropolitanus Pander, Beitr. zur Geogn. d. russ. Reicbes., 1830, p. 

 105, pi. 1, figs. 7-11. 



Favosites hemisphericum Kutorga, Beitr. zur Paleontologie und Geogn. Dor- 

 pats, 1837, p. 40, pi. 9, fig. 3. 



Calamopora fibrosa Eichwald, Silur. syst. in Ebstl., 1840, p. 197. 



Chsetetes petropolitanus Lonsdale, in Murcbison, Verneuil, and Keyserling, Rus- 

 sia and Ural, vol. 1, 1845, p. 596, pi. A, fig. 10. — Keyserling, Raise in d. 

 Petscboraland, 1846, p. 180.— D'Orbigny, Prodr. de Pal., vol. 1, 1850, p. 

 25. — Edwards and Haime, Mon. des Pol. foss., 1852, p. 263. 



Monticulipora petropolitana Edwards and Haime, Brit. Foss. Cor., 1854, p. 264. — 

 Schmidt, Archiv fur Naturk. Liv., Ebst. u. Kurlands, vol. 2, ser. 1, j.858, 

 p. 228. 



Not Diplotrypa petropolitana Nicholson. 



Hemispheric bryozoans from the Paleozoic rocks of many parts of 

 the world have been described and frequently cited in the literature 

 under the specific name of petropolitana because of the belief that 

 they were identical with Pander's Favosites petropolitanus. To-day 



