ADDENDA. 
413 
Genus Pholidops (Hall.) 
In 1859, I proposed the name Pholidops for some minute fossils belonging 
apparently to the family Craniadai, but differing from the true Crania in 
being free or unattached to other bodies, so far as is known. Since that 
time my attention has been called to the figures of Crania antiquissima of 
Eichwald, as given by de Verneuil, in the Geology of Russia and the Ural 
Mountains, vol. ii, plate 1, figs. 12, a, b, c. These are cited by McCoy as 
illustrations of typical form of Pseudocrania. In the figure 12 a, we have the 
characteristic muscular impression of Pholidops; fig. 12 b, can scarcely be¬ 
long to the same species since the apex is subcentral. The figures of 
Pseudocrania divaricata given by McCoy, ( British Paleozoic Fossils,) illus¬ 
trate a different type; the exterior is represented as radiatingly striate 
with a distinct area like Trematis, while the interior presents four mus¬ 
cular pits as in Crania, and quite unlike the Pholidops of our strata. 
Prof. McCoy has cited both the above species as typical forms, but in 
the present state of our knowledge I am not prepared to abandon the 
• Genus Pholidops. 
Pholidops arenaria, (n. s.). 
PLATE III, FIG - . 10. See note, page 82. 
Shell rather above the usual size, subcircular, discoid; beak submarginal 
and slightly elevated; front margin expanded and flattened. 
Surface unknown; interior characterized by a large subcentral muscular 
scar, which in the cast is much deeper on the front margin, and divided 
by a narrow septum. 
This species closely resembles P. oblata of the Schoharie grit, but differs in being 
more nearly circular and in having a much larger area occupied by the muscular 
impression. The largest specimens measure a little more than one-fourth of an 
inch in length. 
Geological formation and locality. In the Oriskany sandstone in the town of 
Knox, Albany county, N. Y. 
[Palaeontology IV.] 
53 
