26 BRYOZOAN FAUNA OF THF ROCHESTER SHALE. 
species in question, the writer is certain that this is an error. The type of the former 
species is bifoliate and exhibits all the characters of the specimens here described and 
figured as Meekopora foliacea, while the types of Lichenalia concentrica are circular, uni- 
laminate expansions with totally different external and internal features. Comparison of 
the figures of the two species given on the plates of the present work will show how little 
allied these two forms really are. 
Occurrence. — A rather abundant fossil in the Rochester shale at Lockport, Rochester, 
and other localities in New York, and at Grimsby, Ontario. 
Catalogue numbers, 35484, 44116, U. S. National Museum. 
Order TR:ET»OSTO:MA.T^V TJlrieli. 
This order, which comprises the "monticuliporoids," is fairly well represented specific- 
ally in the Rochester shale. Species forming large zoaria, such as arc abundant in the 
Mohawkian and Cincinnatian groups, seldom occur, the majority of the forms appearing 
dwarfed or of the small ramose type. Of the number of species so far found, Hall has 
described twelve, and Ulrich, Ringueberg, and Foerste one each. The remaining are here 
regarded as new. 
Family MON-TICITLIPORIDiE Nicholson (emend. TJlrioh). 
Genus ORBIGNYELLA Ulrich and Bassler. 
Orbignyella Ulrich and Bassler, Smithsonian Miscell. Coll. (Quart, issue), XLVII, 1904, p. 18. 
This genus was recently proposed by Mr. Ulrich and the writer for the reception of 
those species which differed from true M onticulipora in having curved diaphragms instead 
of cystiphragms, in wanting the peculiar irregularly granulose wall structure of that genus 
and in possessing true acanthopores. 
Orbignyella expansa (Ringueberg). 
PI. X, figs. 5-8. 
Ch&tetes cxpansus Ringueberg, Bull. Buffalo Soc. Nat. Hist., V. L886, ]>. 20, pi. 2, fig. 17. 
Original description.— Cor &l\um spreading in an irregular lamina. Cells sharply angulate, of various 
shapes from quadrangular to hexagonal; partitions thin; margins of partitions smooth or slightly 
crenate; dentate at their juncture. The oblique rhomboid cell is seen wherever a regular growth took 
place. Length of cells, from one-sixteenth to three-sixteenths of an inch; about ten cells to one-eighth 
of an inch. 
Through the kindness of Doctor Ringueberg the writer was enabled to compare speci- 
mens with the type of the species. The following description is based upon (he type and 
other well-preserved specimens and thin sections: 
Zoarium of lamellate, epithecated expansions composed of one or more layers, each of 
which is usually several millimeters in thickness. Surface smooth, but exhibiting conspic- 
uous clusters composed of zooecia attaining a diameter one and one-half times as great as 
that of the intermacular zooecia. Zooecia polygonal, thin walled, 4 in 2 mm., counting 
from the center of a macula, or 6 of the ordinary ones in the same space; when well pre- 
served, showing minute granulations along the walls and small acanthopores usually at 
the angles. Mesopores wanting. Zooecial tubes thin walled in the short axial region, 
slightly thickened in the peripheral, where they contain a rather crowded series of curved 
diaphragms, three usually occurring in the distance of a tube diameter. 
This species resembles 0. lamellosa (Ulrich) of the Richmond of Illinois in several respects, 
but the smaller zooecia of the latter (8 in 2 mm.) distinguish it at once. All of the asso- 
ciated lamellate forms are so different that comparison is not necessary. 
Occurrence. — Uncommon at Lockport, Niagara Gorge, and Rochester, N. Y., and at 
Grimsby, Ontario. 
Catalogue numbers, 35540, 35541, U. S. National Museum. 
