t 
“American Paleozoic Bryozoa. 2638 
smooth and cylindrical branches, which have altogether a more delicate 
appearance. From 7. halli, Ulrich, it is distinguished by its larger 
branches and smaller cell-apertures. A comparison between the tubes 
in the axial region of the two species, proves that here, those of 7. 
whitfieldi are the largest. The species should also be compared with 
T. spicuiata and Callopora(?) singularis, Hall. From the first it differs 
in its elliptical cell-apertures, more distinct peristome, making it easier 
to distingnish them from the interstitial cells. From the latter, speci- 
mens of 7’ whitfieldi are separated by their smaller cell-apertures, and, 
if Prof. Hall is right, by its tubular interstitial spaces, they being 
stated by that authority to be solid in C. (?) singularis. 
Named in honor of Prof. R. P. Whitfield, the distinguished curator 
of the American Museum of Natural History of New York. 
Formation and locality: Niagara group, at Waldron, Ind. 
STELLIPORA, Hall, 1847. ¢ 
(Pal. N. Y., Vol. L., p. 79.) 
Since publishing a definition of this genus in my scheme of classifica- 
tion in a preceding number of this JournaL (Vol. V., p. 155), I have 
made another, more thorough, examination of the type species, 8. 
anthelotdea, Hall, from the Trenton limestone of New York, which, 
perhaps, is also the only known species of the genus. The zoarium of 
S. antheloidea, being very thin and delicate, and furthermore, very 
irregular in its thickness and distribution over the foreign body in- 
crusted, I found it a matter of no small difficulty to prepare satisfactory 
sections. After a number of trials, I at last succeeded in obtaining a 
series that was in every respect more successful than the first lot. I 
am, therefore, now enabled to furnish the following detailed description 
of the species. 
STELLIPORA ANTHELOIDEA, Hall (Pl. XIV., figs. 1, 1a). 
(Pal.N.Y., Vol. 1., p. 79, Pl. XXVL., figs. 10a-10ce. Not Constellaria antheloidea, of Nicholson.) 
Zoarium thin, growing over and often completely enveloping some 
foreign object (oftenest a crinoid column) to which the undulating 
epithecal membrane adheres, at only limited points. Scattered over 
the surface are conspicuous, more or less prominent stars, each of which 
has a diameter of .l of an inch, sometimes more, rarely less; and is 
composed of a large central, usually depressed, smooth or slightly 
pitted, area, and of from six to twelve prominently elevated, more or 
less wedge shaped ridges, which radiate and slope downward from the 
