208 Mr. R. Etheridge and Dr. H. A. Nicholson 
In 1866 the same authors redescribed * their genus Spheno- 
potertum, abandoned its Actinozoal affinities, and, upon the 
authority of Prof. A. E. Verrill, referred it to the sponges as 
remotely allied to some of the Jurassic forms. The obscure 
striz seen on the interior of the “cups” of their specimens 
are again mentioned ; but their septal character is abandoned. 
To the already known species they here added a new variety, 
S. enorme, var. depressum }. 
We now arrive at a most important point in the history of 
Paleacis and Sphenopoterium. In the same year (1866) Von 
Seebach of Gottingen published, in the ‘Nachrichten der 
kéniglichen Gesellschaft der Wissenschaften zu Gottingen ’ 
for 1866 }, a paper, ‘‘ Die Zoantharia perforata der paliozo- 
ischen Periode,” in which he demonstrated, amongst other 
things, the identity of the two genera, and adopted Haime’s 
name§. This excellent paper was republished with figures in 
the ‘ Zeitschrift der deutschen geologischen Gesellschaft’ for 
1866 ||. Von Seebach considered, from his own researches, 
that Paleacis (= Sphenopoterium) was a true Zoantharian of 
the section Madreporaria Perforata, thus being in accord with 
Milne-Edwards, but differing from the first opinion of Meek 
and Worthen. Again, he demonstrated the identity of Pale- 
acis cunetformis, Kdw. & H., with P. (Sphenopoterium) cunea- 
tum, M.& W., and concluded his paper with a diagnosis of alk 
the American species, describing two additional ones—P. 
eymba, v. Seebach, and P. wmbonata, v. Seebach J. The 
latter were figured in the ‘ Zeitschrift’ for 1866 **, 
Yet another contribution bearing on this subject appeared 
in 1866. Herr Ludwig published a very remarkable paper in 
the ‘ Paleontographica tT, entitled “Corallen aus paliolithis- 
chen Formationen,” apparently having for its chief object 
the complication of synonymy by the introduction of a cloud 
of unusually long and unnecessary names. He described as 
Ptychochartocyathus laxus t{ a form which Prof. de Koninck, 
later on, placed as a synonym of Paleacis cyclostoma, Phill. 
The description appears to bear out this view, although the 
figure, to-our minds, is less satisfactory. Ludwig, however, 
noticed a character very well marked in all our Scotch exam- 
ples of Paleacis—the concentrically wrinkled or ridged base ; 
and he further noticed the papilla-like form of the so-called 
* llinois Geol. Survey Report, vol. ii. p. 145 
+ Loe. cit. p. 146, { Pp. 235-243, § P. 240, 
|| Vol. xvili. pp. 304-310, t. 4. 
4] Nachrichten, pp. 241, 242. ** Pl. 4. figs. 3, 4. 
Tt Vol. xiv. 1865-66, pp. 138-244, 
tt P. 3381, t. 69. fig. 2, a. 
