Chcetetes in the Devonian Strata. — Mohungci'. 61 
name Chcetetes as now defined is no longer applicable in the case. 
As however the Louisville specimens, about to be described, full}' 
correspond, in their structure with Cli (Metes, my formerly used 
provisional designation Chcetetes ponclerosus can now be perma- 
nently settled upon them. 
Their external mode of growth has already been mentioned. 
The width of the rounded polygonal tube orifices, is, as in the 
former, about one-third of a millimeter and of the larger ones, 
on the monticules, about half a millimeter; the intervening walls 
are stout, and not formed of a homogeneous mass of scleren- 
chyma,but obviously show their composition of a circle of solid 
vertical tissue columelles of alternately smaller and larger sizes. 
These columelles are intimately united with their side faces into 
closed channels with simple walls common to the contiguous cavi- 
ties. 
According to the different sizes of the tubes, from twelve to 
sixteen of such columelles may be counted in the circumference 
of an orifice. The larger columelles generally occup}- the angles 
of the tubules, the smaller ones the intermediate part of the walls. 
Cross sections of the columelles under the microscope appear ex- 
actly like intersected acanthopores, as they present themselves in 
tangential sections of some Monticulipora species, but none show 
a central perforation like some of these do in Monticulipora. The 
entire thickness of the walls is occupied by these columelles, the 
larger of which cause a slight indentation of the margins, but in 
this species scarcely ever such strong crest- like projections occur 
as we observe them in the tubes of Chcetetes millejwraceus; other- 
wise, however, the longitudinal striation of the tube walls, corres- 
ponding with their columellar structure, is much more plainly vis- 
ible in thin sections, and even microscopically on cleavage faces 
of the Devonian form, than ever it occurs in specimens of Ch(r- 
tetes milJeporact'us. 
Transverse diaphragms, rather remote in position, are usuall}' 
developed, but in some specimens I could not discover their pres- 
ence. 
From the Devonian limestones of the Eifel I have two different 
species. One of these I collected myself 50 years past in the vi- 
cinity of Gerolstein; it grows in strumose convex masses, and is 
preserved in a porous, granular limestone, with dull fracture. The 
fossil itself is likewise composed of a similar granular calcareous 
