52 BRYOZOAT* FAUNA OF THE ROCHESTER SHALE. 
Semicoscinium tenuiceps (Hall). 
PL XIX, figs. 6,7. 
Fenestella tenuiceps Hali, Nat. Hist. New York, Pal. 11, 1852, p. 1G5, pi. 40D, figs. 2a-b. 
Semicoscinium tenuiceps Ulrich, C.eol. Survey Illinois, VIII, 1890, p. 355. 
Semicos'cinium tenuiceps Grabau, Bull. New York State Mus., No. 45, 1901, p. 171, fig. 72. 
Hall's figures bring out the characters of this species so well that there is no difficulty 
in distinguishing it from the associated fenestellids. The sharp, prominent carina, the 
essentia] feature of the genus; is somewhat flexuous or undulating toward the base of the 
zoarium but straighter in the upper portions. Three to 4 fenestrules may be measured in 
3 mm. longitudinally, and 4 to6 in the same space transversely; 4 to 5 zooeeia to a fenestrule. 
In the typical forms of Semicoscinliim, the fenest rules on the inner or reverse side are 
subrhomboidal or rounded, but in this and other early species the fenestrules are much as 
in Fenestella, thus showing the origin of the genus. 
Occurrence. — Abundant at Lockport, Rochester, Lewiston, and Niagara Falls, N. Y.; 
Grimsby, Ontario. Rare in the Osgood beds at Osgood, hid. 
Catalogue numbers, £5744, 37)745, 35746, U. S. National Museum. 
Genus POLYPORA McCoy. 
Zoarium as in Fenestella, but the median keel is absent and two to eight rows of zooeeia 
are present on a blanch. 
POLYPORA INCEPTA Hall. 
II. XIX. figs. 8-13. 
Polypora incepta Hall, X;it. Hist. New York, Pal. II, L852, p. L67, pi. 401), figs. 5a-f. 
Polypora ina pta Ulrich, Geol. Survey Illinois, v I 1 1 . L890, p. 358, pi. •">■">. fig. I. 
Polypora inct />i<i Grabau, Bull. New York State Mus., No. I."), 1901, p. 172, fig. 73. 
This pretty form was adequately figured by Hall and is easily distinguished from asso- 
ciated fenestellids by its more robust habit of growth and the additional ranges of zooeeia 
The specific characters are as follows; Zooeeia in three or four ranges; apertures oval, 
alternating, branches dividing regularly; dissepiments slender, little enlarged at their 
junction with the blanches. Fenestrules oblong, quadrangular, 4 to 4.5 in 6 mm., meas- 
uring longitudinally, and 7 to L0 in the same space transversely. Reverse side of branches 
longitudinally striated. 
Occurrence. Not uncommon at Rochester and Lockport N. Y., and Grimsby, Ontario. 
Catalogue number.-, 35747, 35748, 44145, U.S. National Museum. 
Genus LOCULIPORA Hall. 
The zoarium in this genus resembles Fenestella except that the dissepiments are short, 
typically reduced to a minimum, and that the branches and dissepiments are carinated, 
the carinas coalescing and their summits much expanded, causing the obverse and reverse 
sides to have much the same appearance. 
Loculipora was founded upon a Hamilton species, Fenestella perforata Hall, in which the 
branches approach so closely together that the zooecial apertures appear to occupy the 
dissepiments as well as the branches. Thin sections, however, show that the dissepiments 
are, as usual, nonporiferous, but are reduced in length to such an extent that the branches 
are brought almost into contact. In the species discussed below, for which type of struc- 
ture the generic term Tectulipora was proposed by Hall, the dissepiments, although more 
pronounced, still exhibit considerable variation in this respect and show their relation to 
the more typical forms of Loculipora. Tectulipora, therefore, could be distinguished from 
Loculipora only by the better development of the solid portions of the dissepiments, but 
at present this feature can not be considered as a good generic character. 
