174 THE GENUS MONTICULIEORA. 



are developed at the angles of junction of adjoining tubes. 

 Longitudinal sections (fig. 2^^, c) show no appreciable differ- 

 ences as compared with corresponding sections of the specimens 

 from the Trenton Limestone. 



Upon the whole, I am disposed to think that there is not 

 sufficient ground for regarding the Hudson River Group 

 specimens as even a permanent variety of the type-form of 

 M. 7uidulata. 



Foruiation and Locality, — Rare in the Trenton Limestone of 

 Peterboro', Ontario. Common (the "puff-ball variety") in the 

 Hudson River Group of Toronto, Weston, and other localities 

 in Ontario. 



Monticulipora (Monotrypa) Winteri, Nich. 

 (Fig. 34-) 



ATonticiilipora IVi/ifcri, Nicholson, Pal. Tab. Corals, p. 323, PI. XIII. figs. 

 5, 5^7, and PI. XIV. figs. 2, 2a, iSig. 



Spec. Char. — Corallum when young, discoid and concavo- 

 convex ; when adult, hemispherical or sub-globular. Young 

 examples may be three or four lines in diameter, and less than 

 two lines in greatest height ; while fully grown specimens may 

 be more than an inch and a half in diameter, and more than an 

 Inch in height. The base is free, or attached to some foreiofn 

 body at one point, and it is either flat or concave, and is 

 covered by a concentrically striated epithecal membrane. The 

 corallites radiate from the base and open upon the upper sur- 

 face by thin-walled polygonal calices. The surface shows 

 clusters of slightly extra-sized corallites, which are only occa- 

 sionally elevated to form low " monticules." The corallites 

 are all uniformly thin-walled, strictly angular or prismatic in 

 form, and sub-equal in size, averaging a quarter of a line in 

 diameter. In internal structure they are all alike, all being 

 provided with delicate, remote, complete, and horizontal 

 tabuloe. 



