BRYOZOA. 137 



Rhinidiclya. I 



Tangential sections give a good idea of the unusual size of the zooecia. 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 

 upwai*d 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. mutaUlis, R. nicholsoni, R.fidelis and R. neglecta, but R. pediculatn and R. trenton- 

 ensis approach it in these respects. The last is, I believe, its nearest congener, but is 

 distinguished readily enough by its nai'rower 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. trenlonensis. Mr. 

 Schuchert's localities are near Beloit, Mineral Point and Janesville. 



Mus. Reg. Nos. 7548, 7554, 7593, 7594. 



RHINIDICTYA PEDICULATA n. 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 bi'anches, 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.* Zooecia 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 flg. 5, (pi. VII) the drawing havinj; been made from a weathered example. 



