122 Cincinnati Society of Natural History, 



with the form to which Prof, Nicholson, in the Pal. vol. ii., Ohio Geol. 

 Survey, gave the name of Chmtetes corticans, which name he after- 

 wards admitted to be synonymous with Edwards and Haime's older 

 name, C. tuherculatns. The two forms can be distinguished by the 

 following differences: In C. iuberculatus the colony is always very 

 thin, the tubercles are decidedl}^ elongated, are regularly arranged^ 

 carry calices of the ordinary size, and never, to any great extent, are 

 compact. The tubes also are not provided with septa of an}- kind. 

 The nature of the tubercles of A. maculata will serve to separate the 

 species from any other species of the genus, excepting A. hirsuta. The 

 numerous minute granules which cover the superior edges of the tube 

 walls in the latter form, are sufficient to distinguish them. 



Forra|p,tiou and locality: occurs at numerous localities in the lower 

 three hundred feet of the Cincinnati Group, as exposed at Ciuciuuati, O. 



Atactopora mdltigranosa, n. sp. (Plate XII., figs. 1, la, Ih.) 



{Eiiy .-Multi , many; granum, a grain.] 



A parasitic bryozoan, attached to species of Orthoceras ; growing in 

 large, thin expansions, frequently in superposed la^-ers, and more de- 

 veloped in certain portions than in others; greatest thickness of any 

 crust observed about three fourths of a line. Surface presenting nu- 

 merous, irregularly distributed monticules, which sometimes have a 

 portion of the summit compact, but usually the entire macula is com- 

 posed of an aggregation of larger sized tubes than the a^-erage; the 

 height and diameter of the tubercles \va-y, but their average dimen- 

 sions are about one quarter of a line in height by one half a line in di- 

 ameter. With the aid of a magnifier the entire surface is seen to be 

 covered with minute granules; they are so numerous that in well pre- 

 served specimens the outlines of the tube orifices can not be traced. 

 Tubes small, rather thin-walled, of unequal sizes, from ten to fourteen 

 of those situated between the monticules, occupying the space of one 

 line, without any minute interstitial tubuli. Tube mouths polygonal 

 or floriform, their margins carrying a row of inwardly projecting, mi- 

 nute tubercles or granules. 



From A. hirsuta this species is distinguished by its more profusely 

 granulated tube walls, groups of larger sized calices, and in the less 

 compact monticules. Tiie growth of A. multigranosa is peculiar, be- 

 ing very irregular, in consequence of a greater development at some 

 parts of the colony than at others; in A. hirsuta the thickness of the 

 expansion is nearly equal in all parts. In A. ortoni, Nicholson, there 



