BRYOZOA. 137 
Rhinidictya.| 
Tangential sections give a good idea of the unusual size of the zocecia. When 
the section cuts deeply the prostrate portion of the cells is shown. Here they have 
the usual characters—thin walls, the longitudinal ones straight, the transverse ones 
at right angles to them in two or three of the central rows, and directed obliquely 
upward in the lateral series, the obliquity increasing with each successive row. Just 
beneath the surface the apertures are elliptical, with a faint line about them, while a 
series of exceedingly minute dots, or a fine double line instead, passes longitudinally 
through the interspaces. 
The large size of the zocecial apertures distinguishes this species from all others 
of the genus known to me. Their hexagonal shape, and the absence of longitudinal 
ridges are two more features that may be relied on in separating it from such species 
as R. mutabilis, R. nicholsoni, R. fidelis and R. neglecta, but R. pediculata and R. trenton- 
ensis approach it in these respects. The last is, I believe, its nearest congener, but is 
distinguished readily enough by its narrower branches and smaller zocecia. 
Formation and locality—The types are from the Birdseye horizon of the Trenton formation at 
Dixon, Illinois. Other examples were noticed in Wisconsin material collected for the State Museum by 
- Mr. Charles Schuchert and sent me for identification. All the specimens are from the ‘‘ Lower Blue 
Beds” of the Wisconsin geologists, in which the species is sometimes associated with R. trentonensis. Mr. 
Schuchert’s localities are near Beloit, Mineral Point and Janesville. 
Mus. Reg. Nos. 7548, 7554, 7593, 7594. 
RHINIDICTYA PEDICULATA 1. Sp. 
PLATE VII, FIGS. 1-5. 
Zoarium bifoliate, apparently growing to but little more than 25 mm. in hight. 
It begins with a small expansion, by means of which. it was evidently attached to 
foreign bodies. Arising from this is a small and short, rounded, subsolid and striated 
footstalk, that soon flattens and spreads into rapidly bifurcating branches, all spread- 
ing approximately in the same plane. The branches have an average width of about 
3.0 mm., are very thin, with unusually sharp edges, wide and obliquely striated non- 
poriferous margin.* Zocecia in from eleven to fourteen ranges, the usual number 
twelve, with the outer row on each side irregular in their arrangement, larger than 
the average, and directed obliquely outward. In the central rows the apertures are 
commonly elliptical, or subangular, and sunken into oblong hexagonal spaces, 
bounded by thin walls, of which the lateral ones form slightly zigzag, low ridges. 
The last feature, however, is to be seen only in the best preserved examples, those in 
the usual condition seeming to have the interspaces rising to the same level on all sides 
of the aperture. Measuring lengthwise along the central ranges fifteen or sixteen 
*The latter is not shown in fig. 5, (pl. VII) the drawing having been made from a weathered example. 
