32 Cincinnati Society of Natural History. 



sub-circular, of two kinds, tlie larger on the ridges of monticules, 

 the smaller in the depressed areas, sometimes granular. 



Obs. The main difference between this and the preceding 

 species is that this one is parasitic, while the other one has a ra- 

 mose corallum. The monticules are similar as are also the calices. 

 The name anf/ie/oidra has been generally though wrongfully given 

 to the previously described form. Though in doubt as to the 

 occ\ixre.ncQ o{ atitheloidea here, the description is inserted to direct 

 attention to its parasitic habit. It may yet be found in our locality. 



Formation and Locality. — Lower Silurian, Trenton Gr , New 

 York. 



Subgenus. C. 



FiSTULiPORA, McCoy, 1849. 



Ann. and Mag. Nat. Hist., ser. 2, III, 130, 1849. Nicholson, 

 Pal Tab. Corals, 304, 1579. Ulrich, Jour. Cin. Soc. Nat. Hist. 

 V, 156. 1882. 



Callopora, Hall. Pal. of New York, II, 144, 1852. Nicholson 

 I.e., 304, 1879. Ulrich, /. c. V, 154, 1882. 



Didymopora, Ul. Jour. Cin. Soc. Nat. Hist., VI, 156, 1882. 



Calloporella, Ul. Ibid, V, 154, 1882. 



Eridopom, Ul. Ibid, V, 137, 1882. 



Leioclerna, Ul. Ibid, V. 154, 1882. 



Cnpipora, Ul. Ibid, V. 157, 1882. 



Chciloporclla, Ul. Ibid, V, 157, 1882. 



HomotrypcUa, Ul. 14th Ann. Rept. Geol. and Nat. Hist. 

 Sur. Minn. 83, 1885. 



Corallum ramose or incrusting. Corallites of two kinds, larger 

 ones oval or circular, often with oblique apertures, surrounded by 

 small, interstitial cells in one or two rows, the apertures generally 

 angular. Macular, if present, generally made up of smaller coral- 

 lites than the average. Interstitial tubes often closed by thin, cal- 

 careous membrane. Walls of calices generally thin. 



Obs. Though rather ill-defined, the species of this sub-genus 

 can be recognized by the larger cells being surrounded by the 

 smaller ones. There is great variation in the form of the corallum, 

 even in what seems to be the same s|)ecies ; the forms vary from 

 ramose, to irregular frondose masses and are also incrusting. The 

 species placed in the sub-genus resemble in most essential features 

 Moiiticiilipora, so that the two cannot, without violence, be sei a- 

 rated. 



