1 88 1.] TJie Paleontologist. 37 



to four, or more, lines in diameter, branching frequently, in a dichotom- 

 ous manner or otherwise. Surface exhibiting conspicuous, regularly 

 rounded elevations, a little over half a line in diameter at the base, and 

 about one line and a half apart from center to center, which are occupied 

 by maculae composed of irregularly shaped pores much smaller than 

 those on other parts of the corallum. The whole surface has a rough- 

 ened aspect, caused by the small, solid, column-like elevations at the 

 angles of many of the calices. Walls of corallites, thin. Calices, sub- 

 circular or polygonal, variable in size, eight or ten in the space of one line 

 between the monticules, with a very few small interstitial tubuli. A 

 transverse section shows the corallites as radiating, apparently, from a 

 central axis to the surface. 



The most decided difference between this species and D. attritus, 

 Nicholson (Pal. of O., vol. ii., p. 194; Annals & Mag. of Nat. Hist, 

 Aug. 1876, p. 93 ; Palseozoic Tabulate Corals., pp. 298-300), is the macu- 

 lae of minute pores, occupying the monticules, distributed regularly over 

 the surface. 



Found near Loveland, O., middle beds of the Cincinnati Group, Low- 

 er Silurian Formation. 



GENUS PTILODICTYA. Lonsdale. 

 Ptilodictya antiqua, sp. nov. James. 



Polyzoary a flattened, two-edged, branching frond, celluliferous on 

 both faces ; transverse section acutely elliptical ; a little more or a little 

 less than half a line in thickness in the middle ; faces of the frond very 

 gently curved to thin, sharp edges. Cells oval, arranged in longitudin- 

 al rows between strong, parallel, more or less sinuous lines, which are 

 increased by implantation where the frond widens, and at the junction or 

 angles of the branches: cell walls oblique and thin, and sharp at top 

 margins, lower lip raised to a level with the longitudinal elevated lines, 

 upper lip depressed : seven or eight cells in the space of one line, meas- 

 uring in a longitudinal direction, and nine or ten transversely. Maculae 

 about one line apart distributed over the surface, very little or none at all 

 raised. The sharp edges of the frond, where perfect, are obliquely stri- 

 ated, not being reached by either the pores or elevated lines. 



The example used for this description is about a quarter of an inch 

 broad just above the first branch, and widens out to nearly half an inch 

 four or five lines above, and is somewhat twisted, and curved from side 

 to side. The tzuisted feature may not be the normal form, but caused by 

 pressure. Dimensions of the Polyzoary unknown, the base and top be- 

 ing both broken away, but the form and surface markings, as described, 

 are so decided as to avoid, it would seem, mistaking this for any other 

 described species. 



W. M. Linney, Esq., of Harrodsburg, Ky., who found this specimen, 

 with others, in that vicinity, names the horizon as the upper part of the 

 Trenton Group, Lower Silurian. 



