50 
only broken by tlie series of strata into wliicli the corallimi is horizontally 
sjilit np. In the axial region the corallites are basaltiform, but in the peri- 
pheral area more or less polygonal, or siibpolygonal ; in the former with occa- 
sional constrictions at long intervals, and in both transversely undulated 
with narrow periodic thickenings, as they aiiproach each final period of 
growth. Average diameter of the corallites about half a millimeter. 
Periodical thickenings of the walls are narrow, ring-like annulations, com- 
paratively wide apart, and separated by unthickened internodcs, giving to 
longitudinal sections of the wall a characteristically moniliform aspect ; but 
they appear to be most abundant and closer in the outer or peripheral zone. 
Acanthopores, as a rule, only developed in the thickened portions of the 
walls, usually at the angles of junction of the corallites, but occasionally in 
other parts of the former. Tabulse very sparsely developed in the axial 
region, but comparatively numerous in the peripheral region, corresponding 
in general with the thickened annulations ; they are complete and imper- 
forate, and concave in a contrary direction to the growth of the corallites. 
Surface undulating, bearing monticules. 
Ohs . — The type specimen of this sj^ecies is a mass about four inches 
and a half in length, composed of long basaltiform corallites, with a very 
gentle outward inclination, and evidently taken from the axial of a 
very large corallum. This specimen is now in the Geological Department of 
the Natural History Branch of the British Museum. 
The corallum of Stenopora crlniia at times undoubtedly attained to a 
very large size ; large masses, to the naked eye, having a wonderful resem- 
bla nee to the large Chcuteles radians, Pischer, of the Bussian Carboniferous 
Limestone. Dana mentions^ a specimen of S. crinita six inches in diameter. 
A similar one to this is in the Collection, and another five inches in diameter. 
The corallum is invariably large, forming hemispherical, globose, massively 
tabular expansions, with an undulating surface, at times rising into lobate 
extensions, and almost becoming digito-palmate, but, so far as known, never 
ramose. Irregularities in growth sometimes occur, but the coral a2)pears to 
have jiossessed a great facility for recovering the direction of its growth. 
The corallites are sometimes deflected from their course, immediately above a 
j^eriodical cessation of activity, rejiresented by the moniliform constrictions ; 
but the original line or direction of growth is almost always recovered. 
■ Wilkes’ U. S. Explor. Exped,, 1849, Vol. X, Geology, p. 711. 
