BOTANY AND ZOOLOGY. 
95 
upper side, into little eminences. The distinction into beds is produced 
by variations in the density of the coralline substance. Masses of 
coral occur, several feet in length, and even in diameter. The dis¬ 
tance of the pustules 4 millimetres, or .16 inch; and the mean thick¬ 
ness of the lamina* one-fifth of a millimetre, or .008 inch. 
Stromatopora monticulifera has a structure and form like the pre¬ 
ceding, but differs therefrom in the much larger and more remote 
eminences on the upper surfaces of the concentric beds, and in the 
larger and more distinctly radiating character of the passages which 
diverge from the apices of the monticules. These passages, on the ex¬ 
posed surface, are little, flexuous, somewhat branching furrows, which 
diminish in size and disappear within 5 millimetres or .2 inch. The 
distance of the monticules is from 7 to 10 millimetres. This coral at¬ 
tains a diameter of at least 3J metres or 12 feet. I have found it in 
Little Traverse Bay, on the west side of the State; on Thunder Bay 
Island, on the east side; and on Kelly’s Island, near Sandusky, Ohio. 
The two species thus described evidently possess some affinity with 
the verrucose forms embraced by Goldfuss under S. polymorpha , and 
separated by D’Orbigny under his genus Sparsispongia. The dis¬ 
tinct, vermicular perforations suggest, also, an affinity with Caunopora , 
Phillips. The great regularity and persistence of the eminences, how¬ 
ever, render it impossible to account for them, as Goldfuss did, by an 
unequal deposition of coralline substance, or by original inequalities in 
the primitive body upon which the corallum was formed. Indeed, 
though I have seen ship-loads of these corals, I have never detected 
evidence that they were in any sense incrusting. The concentric 
layers are only segments of circles passing transversely across the 
spheroidal, or more often elongated mass, — many of which I have 
seen standing erect in the face of an escarpment, with the ruins of 
other beings and other generations strewn around them. The debris 
of these organisms have formed literal coral reefs, and constitute, in 
Little Traverse Bay, almost the entire mass of a bed of buffish lime¬ 
stone twenty-five feet in thickness. 
Neither can I agree with Goldfuss, that the radiating furrows and 
perforations are caused by attrition or disintegration of the apica 
portions of the eminences. They are always most distinct on the 
freshly exposed surfaces, and show as well on the under side as the 
upper side of the layers. 
