338 AMERICAN FOSSIL BRYOZOA. [bull. 173. 



Pachydictya alcyone (Billings) — Continued. 



1893. Pachydictya alcyone. Ulrich, Geol. Minnesota, III, p. 146. 

 Anticosti: Anticosti Island. 

 Obs. This may prove a synonym for Pachydictya crassa (Hall). 



Pachydictya arguta Ulrich. See Pachydictya crassa (Hall). 



Pachydictya bifurcata (Hall). 



1853. Eschara bifurcata. Van Cleve (Mss.) . 



1883. Stictopora bifurcata. Hall, Twelfth Ann. Rep. Indiana Geol. Nat. Hist., p. 



267, pi. xiii, 3, 4. 

 1887. Pachydictya bifurcata. Foerste, Bull. Sci. Lab. Denison Univ., II, p. 163; 



ibid.,111, 1888,pl. xv,9. 

 1895. Pachydictya bifurcata. Foerste, Geol. Sur. Ohio, VII, i:>. 599, pi. xxviii, 9_ 

 Clinton: Dayton and Fair Haven, Ohio. 



Pachydictya bifurcata-instabilis Foerste. 



1887. Pachydictya bifurcata var. instabilis. Foerste, Bull. Sci. Lab. Denison 



Univ., li, p. 164; ibid., Ill, 1888, pi. xv, 10. 

 1895. Pachydictya bifurcata var. instabilis. Foerste, Geol. Sur. Ohio, VII, p. 699, 



pi. xxviii, 10. 

 Clinton : Near New Carlisle, Ohio. 



Pachydictya conciliatrix Ulrich. See Trigonodictya conciliatrix 

 (Ulrich)"^, 



Pachydictya crassa (Hall). 



1852. Stictopora crassa. Hall, Pal. New York, II, p. 45, pi. xviii, 4a-c. 



1874. Ptilodictya crassa. Nicholson and Hinde, Canadian Jour., new ser., XIV, 



p. 142. 



1875. Ptilodictya crassa. Nicholson, Pal. Province Ontario, j). 45. 

 1893. Pachydictya crassa. Ulrich, Geol. Minnesota, III, p. 147. 

 1866. Ptilodictya rustica. Billings, Catal. Sil. Foss. Anticosti, p. 36. 

 1893. Pachydictya rustica. Ulrich, Geol. Minnesota, III, p. 146. 

 1866. Ptilodictya arguta. Billings, Catal. Sil. Foss. Anticosti, p. 36. 

 1893. Pachydictya arguta. Ulrich, Geol. Minnesota, III, p. 146. 



1887. Stictopora scitula. Hall and Simpson, Pal. New York, VI, pi. Ixi, 24, 25. 



1893. Pachydictya scitula. Ulrich, Geol. Minnesota, III, p. 147. 



1889. Ptilodictya farctus. Foerste, Proc. Boston Soc. Nat. Hist., XXIV, p. 328, 



pi. vi, 31. 

 1895. Pachydictya farctus. Foerste, Geol. Sur. Ohio, VII, p. 599, i)l. xxxi, 31. 

 1889. Ptilodictya rudis. Foerste, Proc. Boston Soc. Nat. Hist., XXIV, p. 329, 



pi. vi, 33. 

 1895. Pachydictya (Rhinidictya) rudis. Foerste, Geol. Sur. Ohio, VII, p. 599, 

 pi. xxxi, 32, 33. 

 Clinton: Wayne County, New York; Eaton, Ohio; Flamborough and Dun- 

 das, Ontario. 

 Anticosti: Anticosti Island. 

 Niagara: Lockport, New York. 



Obs. Though rather meager in details and varying as to the number of 

 rows of apertures on the frond, there is substantial agreement in all the 

 descriptions cited above. Evidently we have in this species a cosmo- 

 politan form. 



Pachydictya elegans Ulrich. 



1893. Pachydictya elegans. Ulrich, Geol. Minnesota, III, p. 154, pi. viii, 18, 19, 

 pi. ix, 8, 9. 

 Trenton: St. Paul, Minnesota; Decorah, Iowa. 



