ulrich-bassler] revision of paleozoic bryozoa 275 



seventeen. The preservation of the specimen is not favorable enough 

 to show either the pores on the threads or character of the centers. 



Occurrence. — Corryville beds of the Lorraine formation, Cincin- 

 nati, Ohio. 



Cat. No. 43,149, U. S. N. M. 



VINELLA RADICIFORMIS (Vine) 



(Plate LXVIII, 7) 



1881. Ascodictyon radians Vine (part), Quart. Jour. Geol. Soc. London 

 (provisional placement), xxxvii, p. 619. 



1882. Ascodictyon radiciforme Vine, Ibid., xxxviii, p. 53, figs, i, 3. 

 1884. Ascodictyon radiciforme Vine, Ann. & Mag. Nat. Hist., sen 5, 



XIV, p. 83, figs. 1-5. 

 1887. Ascodictyon radiciforme Vine, Proc. Yorkshire Geol. & Polyt. Soc, 

 IX, pp. 183-4, pl- 12, fig. 5. 



1892. Ascodictyon radiciforme Vine, Ibid., xii, p. 87. 



1893. Vinclla radiciformis Ulrich, Pal. Minnesota, in, pt. i, p. 113. 



This species is distinguished from V. rcpcns by the much greater 

 tenuity of the zoarial threads, their average thickness in the one being 

 about 0.08 mm. and in the other between 0.03 and 0.04 mm. In the 

 immediate vicinity of the centers the radii are sUghtly swollen, and 

 this character affords another point of difference. 



In the typical form of the species the nuclei of the rays are widely 

 separated and often difficult to distinguish from the points where the 

 rays merely cross each other. The rays often appear to, and prob- 

 ably do, bifurcate, and, on the whole, seem to meander about without 

 much order. Sometimes they suggest Hetcroncma capiUarc, in 

 which there are no nuclei, but, as they are considerably finer than in 

 that species, there is little excuse for confusing them. 



Occurrence.- — Buildwas beds of the Wenlock shales, Shropshire, 

 England ; Rochester shales, Lockport, New York. 



Cat. No. 43,146, U. S. N. M. 



VINELLA RADICIFORMIS CONFERTA Ulrich 



(Plate LXVIII, 5, 6) 

 1893. Vinella radiciformis var. confcrta Ulrich, Geol. Minnesota, in, p. 

 113, fig. 8, c, d. 



This variety or closely related species may be distinguished usually 

 without much trouble by the much greater frequency of its nuclei, 

 more numerous radii, and slightly thicker threads. In the larger 

 nuclei the center is commonly depressed. As to the radial threads, 

 they are sometimes jointed, and in such cases each of the rather short 

 internodes carries a single pore. 



