CORALS AND BRYOZOA. 
11 
ALVEOLITES, Lamarck. 1801. 
Alveolites explanatus. 
PLATE XIII, FIGS. 15, Iti. 
Alveolites explanatus, Hall. Report of State Geologist for 1SS3. Expl. pi. 13, figs. 15, 16. 
Corallum growing as irregular incrusting expansions upon other organisms. 
Cell tubes small, less than 1 mm. in longest diameter, compressed and rising 
very obliquely to the surface; marked by obscure longitudinal striae. 
The specimens of this species which have been observed, occur in explanate 
masses on Favosites and Stromatopora, and seldom weathered so as to exhibit 
their exterior structure, but are usually shown in sections and polished cuttings. 
It presents very little detail of form or structure, and is of little interest except 
as being the only species of the genus noticed from the rocks of this age. 
Formation and localities. In the lower Pentamerus limestone of the Lower 
Helderberg group, near Cedarville, Herkimer county ; near Clarksville, Albany 
county, and at Schoharie, N. Y. 
C I-I M T E T E S, Fischer. 1837. 
CmETETES COLLICULATUS. 
PLATE VIII, FIGS. 1-4. 
ChcBtetes colliculatus, Hall. Thirty-second Rept. N. Y. State Mus. Nat. Hist., p. 148. 1879. 
“ “ “ Report of State Geologist for 1882. Expl. pi. 8, tigs. 1-4. 1883. 
Corallum hemispheric. Base generally flat; sometimes very concave, in 
which case the corallum consists of a depressed conical mass. Base covered 
by a strongly wrinkled epitheca. Cells polygonal, from quadrangular to 
hexagonal, nearly equal in size; diameter at the aperture about .50 nun.; 
walls thin and slightly undulating. Septa very thin, distant, five in the 
space of 5 mm. Surface marked by monticulse about 2 mm. in height, the 
centers of which are distant from each other 5 mm., with cells the same 
size as the others. 
The largest specimen observed has a diameter at the base of 35 mm., and 
a height of 25 mm. 
