FENESTELLIDS. 5 1 
F. cribrosa may readily be distinguished from associated fenestellids by the small size and 
quadrangular shape of the fenestrules, the wide branches, and striated noncelluliferous side. 
On the celluliferous face the characters to be noted are the occurrence of protruding zooecial 
apertures generally two but sometimes three to a fenestrule. The carina is moderately 
elevated but conspicuous spines are developed, averaging two to a fenestrule. 
Occurrence. — Rather rare at Lockport; not uncommon at Middleport, N. Y. 
Catalogue number, 35553, U. S. National Museum. 
Fenestella elegans Hall. 
PI. XIX, figs, l, 2. 
Fenestella elegans Hall, Nat. Hist. New York, Pal. II, 1852, p. 164, pi. 40D, figs. la-g. 
Fenestella elegans Grabau, Bull. New York State Mus., No. 45, 1901, p. 170, fig. 70. 
The characters of this as well as most of the other Rochester shale fenestellids have been 
well illustrated by Hall, and the following brief description and measurements are given 
for completeness; 
Fenestrules quadrangular, 3 to 4 in 3 mm., measuring longitudinally, and 6 in 3 mm. 
transversely. Zooeeia in two ranges separated by a sharp, moderately elevated carina, 
which in perfect specimens bears small spines at intervals of about 0.4 mm.; 4 zooeeia to 
a fenestrule. On the reverse side the fenestrules are quadrangular and two or three fine 
striations mark the branches. 
Occurrence. — Fragments are common at Lockport, the type locality, and at all the other 
localities in western New York; good specimens occur also at Thorold, Hamilton, and 
Grimsby, Ontario. 
Catalogue number, 44143, U. S. National Museum. 
Genus PT1LOPORELLA Hall. 
Like Fenestella, except that at regular intervals the branches are considerably thickened 
and form rib-like supports. 
Ptiloporella nervata (Nicholson). 
PI. XXIV, figs. 24, 25; PI. XXVI, figs. 5, 6. 
Fenestella nervata Nicholson, Pal. Ohio, II, 1875, p. 204, pi. 25 figs. 11, 11a. 
Ptiloporella nervata Miller, North American Geol. and Pal., 1889, p. 319. 
Several large examples and numerous fragments of this species were found at Grimsby, 
Ontario, and at Lockport, N. Y., one of them collected by Mr. Ulrich showing a spread of 
160 mm. The rib-like development of the branches at regular intervals will cause the 
recognition of the form to be easy. The measurements of the Rochester shale specimens 
agree in all essential respects with the Ohio types as figured by Nicholson, so that there 
seems to be no question of their specific identity. For convenience of reference, Nicholson's 
figures are reproduced on PI. XXIV. 
Occurrence. — Rochester shale, Lockport, N. Y., and Grimsby, Thorold, and Hamilton, 
Ontario; Osgood beds, Osgood, Ind. Nicholson's types were found in the Niagara lime- 
stone at Cedarville, Ohio. 
Catalogue numbers, 35743, 44144, U. S. National Museum. 
Genus SEMICOSCINIUM Prout. 
Zoarium as in Fenestella save that the zocecia are developed on the outer side of the 
branches and that the keel has a much expanded summit. 
