161 



M0LLU8C0IDEA. 



POLYZOA. 



Stomatopora Canadensis. (N. Sp.) 



Plate 18, figs. 4 and 4a. 



Zoarium adnate, consisting of frequently branching, uniserially arranged 

 zocecia. Zooecia slender, clavate, each about 0-6 mm. in diameter at the 

 proximal or narrow posterior end, increasing gradually in size to 0'3 

 mm. at the rounded anterior end, and averaging about 1 mm. in length. 

 Apertures small, circular, nearly terminal, about O'S mm. in diameter. 



Little Black Island, Lake Winnipeg, J B. Tyrrell, 1889: one specimen. 



Mr. E. O. Ulrich, who has examined the specimen upon which this 

 species is based, thinks that it is " most nearly related to S. Proutana, 

 Miller,* but that it has much larger zocecia.'' He is of the opinion that 

 it is quite distinct from S. inflata (the Alecto inflata of Hallf ), and that 

 in S. arachnoidea [Aulopora arachnoidea, Hall |) "the zocecia are smaller 

 and less constricted proximally.'' 



Pachydictya magnipoba, Ulrich. 



Pachydictya ma/jnipora, Ulrich 1889. Geol. Surv. Canada, Contr. Micro- 

 Pal. Oambro-Silur. rooks, etc., p. 43. 



Lower Fort Garry (St. Andrews), Dr. R. Bell, 1880 : the type and 

 only specimen known to the writer. 



Pachydictya acuta, Hall. (Sp.) 



Stictopora(?) acuta, Hall 1847. Pal. N. York, vol. I., p. 74, pi. 26, 



figs. 3, a-b. 



Ptilodictya acuta, Billings 1863. Geol. Canada, p. 158, fig. 121, and p. 



941. 



I. 11 Nicholson 1875. Rep. Pal. Prov. Ontario, p. 12, fig. 3. 



Pachfidictfia acuta, Ulrich 1886. Fourteenth Ann. Rep. Geol. and Nat. 



Hist. Surv. Minn., p. 67. 

 ■1 11 i 1889. Geol. Snrv. Canada, Contr. Micro- 



Pal. Cambro-Silur. rocks, etc., p. 44. 



11 11 1893. Lower Silur. Bryoz. Minn, (advance 



copies from Final Rep. Geol. Minn., vol. 

 III., pt. 1) p. 155, pi. 8, figs. 11-17, and 

 pi. 9, fig. 7. 



*. Journal Cincinnati Society of Natural History, vol. V., pt. 2, p. 39. See also Ulrich 's 

 Lower Silurian Bryozoa of Minnesota, p. 117, pi. 1, figs. 8-12. 



+ Palseontology of the State of New York, vol. I. (1847), p. 77, pi. 26, figs. 7, a-b. 

 See also Ulricb's Lower Silurian Bryozoa of Minnesota, p. 117, pi. 1, figs. 13-21. 



J Palaeontology of the State of New York, vol. I., p. 76, pi. 26, figs. 6, a-c. 



3 



