BEYOZOA. 



Stomatopora. 1 



upper surface of the threads ; about eleven in 2.5 mm. Zooecia unknown, probably 

 deciduous." 



In the Hudson River species, V. radialis, the average thickness of the stolons is 

 a little less. They are also straighter and arranged quite regularly in a radial man- 

 ner. In the Niagara form, V. radiciformis, var. conferta, the stolons are likewise more 

 slender and the nuclei much more frequent. 



Formation and locality Rare in the upper third of the Trenton shales at St. Paul, Minnesota. All 

 the specimens seen have grown upon valves of Strophomena septata Winchell and Schuchert. 



Sub-order CYCLOSTOMATA, Busk. 

 Genus STOMATOPORA, Bronn. 



Alecto, LAMX., 1821, BLAINVILLE, JOHNSTON, M. EDWAKDS, BUSK, etc. (Not Alecto, Leach, 1814.) 



Stomatopora, BRONN, 1825, Pflanzenth., p. 27. D'ORBIONY, 1852, Pal. Franc, t. v, p. 833. HAIME, 



1854, Bry. Foss. Form. Jurassic, p. 159. ULKICH, 1882, Jour. Gin. 

 Soc. Nat. Hist., vol. v, p. 149, and 1890, Geol. Sur. 111., vol. viii, 

 p. 367. MILLER, 1889, N. Amer. Geol. and PaL, p. 325. 



Stomatopora (part.), HINCKS, 1880, Brit. Mar. Polyz., p. 424. 



Aulopora (part.), GOLDFUSS, REUSS, HALL, NICHOLSON. 



Zoaria adnate ; zoiecia subtubular, club-shaped, or ovate, not immersed, arranged 

 in single branching series ; apertures subterminal, more or less elevated, circular ; 

 walls finely porous. 



Type : Alecto dichotoma Lamouroux. 



In drawing up this diagnosis I continue to follow Jules Haime and d'Orbigny in 

 discriminating between the uniserial and multiserial forms, despite the fact that a 

 tendency to unite them under one name has of late become manifest. Hincks, for 

 instance, places species here having precisely the same zoarial habits as the Probo- 

 scina frondosa (pi. 1, fig. 28) of the Hudson River rocks. He would probably go far 

 enough in this direction to include even Berenicea minnesotensis. And yet he retains 

 Diastopora, with Berenicea as a synonym. The resulting classification is, to my mind, 

 anything but satisfactory. With me the greatest difficulty is, not to separate the 

 uniserial forms, but to draw a line between Berenicea (as typified by B. diluviana 

 Lamouroux) and the bi- and multiserial forms of which Proboscina auloporoidea 

 Nicholson, sp., P. tumulosa, P. frondosa Nicholson, sp., and Berenicea minnesotensis are 

 progressive examples. That some of these, and several Secondary, Tertiary and re- 

 cent species of this type, sometimes have the zooecia arranged uniserially at the base 

 and at the beginning of the branches is scarcely a sufficient reason for regarding them 

 as congeneric with such invariably uniserial forms as Stomatopora dichotoma Lamou- 

 roux, S. proutana S. A. Miller, S, inflata Hall, sp., and a host of others. As I view the 



