12 BllYOZOAN FAUNA OF THE ROCHESTER SHALE. 
outline. From a central stolon or series of segments, lateral branches are given off at 
approximately right angles, and in the same manner these divide again until the result is a 
network of anastomosing branches arranged pinnately. Length of segments somewhat 
variable, 3 to 3.5 in 2 mm. Orifice not observed because of the preservation, but probably 
situated in the swollen end of the segments. 
The differences between this species and R. venosa Ulrich a from the Richmond group 
are slight, the length and arrangement of the internodes and stolons being practically the 
same in each. R. attenuata, however, may be distinguished by the extreme tenuity of the 
internodes and stolons, and by the comparative rigidity of their arrangement. The zoceeial 
and zoarial features of the two, if preserved, would probably show more differences, but 
as the excavations alone have been found, slight variations must serve in discriminating 
species. 
Occurrence. — The figured types were found in the Rochester shale at Lockport, N. Y., 
where specimens are not uncommon. Examples have also been found in the same formation 
at Rochester and Lewiston, N. Y., in the Niagara Gorge, and at Grimsby and Thorold, 
Ontario. The Clinton limestone at Mifflintown, Juniata County, Pa., and the Waldron 
shale at Waldron, Ind., and atNewsom, Tenn., furnish specimens which can not be separated 
from the typical form. 
Catalogue numbers, 43116, 43117, 35733, 35477, U. S. National Museum. 
Family VINELLID^G TJlrich. and. Bassler. 
Genus VINELLA Ulrich. 
Zoarium parasitic, consisting of very slender, tubular threads or stolons, arranged more 
or less distinctly in a radial manner. Surface of threads with a single row of small pores, 
which may be wanting locally and may vary considerably in the degree of their separation. 
Zocecia unknown, probably deciduous. 
Vinella radiciformis (Vine). 
PL IV, figs. 2, 3. 
Ascodictyon radians Vine (part), Quart. .lour. Geol. Soc. London (provisional placement). XXXVII, 
1881, p. 619. 
Ascodictyon radicif or me Vino, ibid., XXXVIII, 1822, p. 53, figs. 1, 3. 
Ascodictyon radiciformc Vine, Ann. and Mag. Nat. Hist. (5), XIV, 1884, p. 83, figs. 1-5. 
Ascodictyon radicif orme Vine, Proc. Yorkshire Geol. and Polytech. Soc, IX, 1887, pp. 186-4, pi. 12, fig. 5. 
Ascodictyon radiciforme Vine, ibid., XII, 1892, p. 87. 
Vinella radiciformis Ulrich, Geol. and Nat. Hist. Survey Minnesota, Final Kept., Ill, pt. 1, 1893, p. 113. 
Vinella radiciformis Ulrich and Bassler, Smithsonian Miscell. Coll. (Quart, issue), XLV, 1904, p. 275. 
1)1. 68, fig. 7. 
This species, originally described from the Wenlock shales, has been noted at a number 
of American localities. Its delicate zoaria are generally found incrusting smooth-shelled 
brachiopods, crinoid columns, or the epithecated side of bryozoa, such as explanate species 
of Fistulipora or Lioclema. The rather widely separated nuclei and the extreme tenuity of 
the radiating threads are especially characteristic. Near the centers themselves the radii 
are slightly swollen, but their average thickness elsewhere lies between 0.03 and 0.04 mm. 
Sometimes the threads seem to bifurcate or to wander about without much order, and often 
the nuclei are difficult to distinguish from the points where the threads merely cross. 
Occurrence. — Buildwas beds of the Wenlock shales, Shropshire, England; Rochester 
shales, Rochester and Lockport, N. Y.; Grimsby, Ontario; Waldron shale, Waldron, lnd 
Clinton formation, Sevenmile Creek, near Eaton, Ohio. 
Catalogue numbers, 35476, 43145, 43146, U. S. National Museum. 
a Ulrich, Jour. Cincinnati Soc. Nat. Hist., II, 1879, p. 20, pi. 7, figs. 24, 24a. 
