2 24 THE GENUS AIONTICULIPORA. 



Horizon and Locality.— Cmcmw^ti Group, Cincinnati, Ohio. 

 (Common.) 



Monticulipora (Peronopora) molesta, Nicli. 



(PI. VI. figs. 2-2^.) 



Spec. Char. — Corallum usually frondescent, having the form 

 of extended and undulated, sometimes lobed or palmate, ex- 

 pansions, which may attain a considerable size, and vary In 

 thickness from two to four or five lines. Rarely, the corallum 

 Is massive. Surface covered with numerous prominent, con- 

 ical, or slightly elongated monticules, placed at distances of 

 half a line to a line apart, and composed of corallltes which do 

 not differ conspicuously in size from those forming the mass of 

 the corallum. Calices polygonal, thin-walled, sub-equal, from 

 I -85th to I -90th Inch in diameter, with a few smaller inter- 

 stitial apertures scattered amongst them. Corallltes of two 

 kinds, large and small. The large corallltes are much the 

 most numerous, are thin-walled and polygonal, and are fur- 

 nished for the most part with Incomplete tabulae. In these 

 tubes the tabuke form a series of lenticular vesicles alonof one 

 side of the visceral chamber, and a moderate number of straight 

 or slightly concave tabular extend from these to the opposite 

 side of the cavity of the corallite. The small corallltes are 

 comparatively few In number, are angular In shape and vari- 

 able In size, and are crossed by numerous, complete, horizontal 

 tabulse. 



Obs. — In Its general form and mode of growth, as well as in 

 almost all Its superficial characters, this species precisely re- 

 sembles M. manimulata, D'Orb., and without the preparation 

 of thin sections it Is often quite Impossible to definitely deter- 

 mine to which of the two types a given specimen may belong. 

 Almost the only superficial character that is of any use In this 

 connection Is the comparative paucity of the small interstitial 

 corallltes In this form (PI. VI. fig. 2d), as compared with what 

 we find In M, luamnutlata. The monticules also are more uni- 



