60 BRYOZOAN FAUNA OF THE ROCHESTER SHALE. 
Rhinopora cur v ata Ringueberg. 
PI. XXII. figs. 12, 13. 
Rhinopora curvata Ringueberg, Bull. Buffalo Soc. Nat. Hist., V, 1886, p. 19, pi. 2, fig. 14. 
Original description.- Corallum very thin; foliate. Cells round or roundish oval, placed near the 
upper side of the thin pustulate calices that rise gradually from the surface at their lower side, thereby 
giving an upward direction to the cells. The cells are arranged closely in regular rows that cross each 
other diagonally; thus making a quincunx disposition of them; the regularity of the rows is some- 
times disturbed by the bifurcation of a row as the frond increased in size. 
Curve amounting to the width of three rows in one-half inch. Cells seven to one-eighth of an inch in 
the rows. 
This coral hears some resemblance to A', verrucosa of the Clinton group; winch differs, however, in 
the ceils being much more prominent, the pustulose character being more defined, rising abruptly from 
the surface, in having the cell opening cent rally located, and by its small cells. 
Rhinopora curvata may be readily distinguished from all associated Rochester shales 
species by its broad, bifoliate growth, large zooecia (1 in 2 mm., measuring along the diag- 
onal rows), with the posterior portion of the peristome considerably elevated, and the, 
arrangement of the apertures in well-defined diagonal lines. 
Only a few specimens of this species have been studied, and none of these exhibits the 
characteristic covered canals of typical Rhinopora. Otherwise, however, the internal 
structure is essentially the same, and also differs in no way hut method of growth from 
that of Lichenalia. 
Occurrence. Rochester shale, Lockport, X. Y., and Grimsby, Ontario. 
Catalogue number, ^o7(>7, [J. S. National -Museum. 
Genus LICHENALIA Hall. 
Lichenalia Hall, Nat. Hist. New York. p a l. II. 1852, p. 171. 
Lichenalia Nickles and Bassler, Bull. U. S. Geol. Survey No. \7'A, p. 54. (Not Lichenalia of othej 
authors.) 
This genus was founded by Hall upon thin, epithecated, subcircular expansions occur- 
ring in the Rochester shale at Lockport, designated by him as Lichenalia concentrica Ir 
parting the shale, the rough celluliferous sides of these expansions naturally adhere morc 
closely to the matrix, and as a result the. noncelluliferous, epithecated side is usualfl 
observed. Associated epithecated bryozoa from Lockport and elsewhere have beer 
referred to the species irrespective of any other character, and Lichenalia concentrica is 
usually quoted as a characteristic Niagaran fossil wherever the rocks of that formation an 
studied. Here the value of thin sections is demonstrated, as it is only by their aid t ha 
the true relations of Lichenalia could be definitely ascertained. Hall's original definition: 
of the genus and species are of value only in that the genotype is restricted to the thin 
epithecated expansions occurring at Lockport and elsewhere in western New York. Al 
his later definitions of tin- genus are based on species of Fistulipora, which are in no mannl 
related to the original types of Lichenalia. A study of Hall's type of L. concentrica am 
of other examples from New York shows that the generic characters arc as follows: " Zoar 
ium a subcircular unilamihar expansion; zooecia prostrate; elongate-subrhomboidal, wit! 
direct subtubular vestibules; apertures rounded, with peristome much elevated on the pen 
terior side; interspaces depressed, ( () cellulose." 
To this definition of Nickles and the writer may he added the following remarks. Tin 
sections show that, as in Rhinopora, the surface of Liclicnalia concentrica is traversed b 
slender, bifurcating ridges which in reality are closed canals. These probably represeti 
the. maculaa of other bryozoa, and are more often sect) in thin sections because, as mer • 
tioned above, the surface is seldom observed. The occurrence of these canals in both Rk 
nopora and Lichenalia and the other points of agreement of the two genera leave the 
different methods of growth as the only distinguishing character. The cellulose ( intej 
spaces mentioned in the above definition of the genus have been determined only by tV 
study of thin sections. The few specimens showing the celluliferous face have been i 
