PHYLLOPORINIDvE. 49 
Genus PSEUDOHORNERA Roemer. 
Pseudohornera Roemer, Leth. geog., Leth. Pal., I, Atlas, 1870, expl. pi. 12. 
Drymotrypa Ulrich, Geol. Survey Illinois, VIII, 1890, p. ?m. 
Drymotrypa Miller, North American Geol. and Pal., First App., 1892, p. 684. 
Thamnocella Simpson, Fourteenth Ann. Rept. State Geol. New York for 1895, 1897, p. 525. 
Drymotrypa Nickles and Bassler, Bui!. U. S. Geol: Survey No. 173, 1900, p. 235. 
It is unfortunate that the well-defined genus Drymotrypa must be abandoned in favor of 
the name Psfudohornera, which not only lacks description but also expresses a false relation- 
ship; but as both genera were founded upon the same species, Hall's Rett pora diffusa, there 
is no doubt of their identity. In the explanation of PI. 12, figs. 2a, 2b, of the work cited, 
Roemer gives the new name Pseudohornera diffusa to Hall's speci< s and illustrates the genus 
by copies of Hall's figures, intending, no doubt , to define the genus in the text, which, however, 
never appeared. The rules of nomenclature require recognition of generic names founded 
upon well-illustrated species, and, as Pseudohornera mi ets with this requirement, the name 
is here used in place of Drymotrypa. Th< writer may be accused of inconsistency in recog- 
nizing Pseudohornera in place of Drymotrypa and then accepting Phylloporina instead of the 
much earli< r name Subretepora, both of which were founded upon the same type of structure, 
but the two are not parallel casts. Pseudohornera is founded upon good figures correctly 
illustrating the type species while D'Orbigny's Subretepora was proposed for Intricaria 
Maihrata Hall, which was both figured and described incorrectly. 
The writer is indebted to Miss Margaret W. Moodey,of the United Stat< s Nat ional Museum, 
for calling attention to Pseudohornera, as well as for many other valuable bibliographic 
references which she has discovered during the preparation of a catalogue of North American 
invertebrate fossils. 
The zoarium in Pseudohornera is of dichotomously dividing branches, celluliferous on one 
side and longitudinally striated on the reverse. The zocecia are in s( vend ranges and spring 
from a thin double plate, beneath which is a number of vesicles; the vestibules expand from 
the orifice to the angular apertures. 
Pseudohornera niagarensis (Hall). 
PI. XVIII, fig. 20; PI. XIX. figs. 14-16. 
Fenestella n. sp. Hall, Nat. Hist. New York, Pal. 11, 1852, pi. 40D, fig. 4. 
Thamniscvs ? Niagarensis Hall, Twenty-eighth Ann. Rept. New York State Mus. (doc. ed.), 1870, pi. 11, 
figs. 22-25; ibid. (Mus. ed.), 1879, p.. 126, pi. 11, figs. 22-25. 
ThamniscvrS niagarensis Hall, Eleventh Ann. Rept. Indiana Geol. Nat. Hist., 1882, p. 254, pi. 10, figs. 
22-25. 
Drymotrypa niagarensis Ulrich, Geol. Survey Illinois, VIII, 1890, p. 299. 
Thamniscus Niagarensis Simpson, Fourteenth Ann. Rept. State Geol. New York, for the year 1894, 1897, 
pi. 9. figs. 15-17. 
The collections from the Rochester shale contain several well-preserved specimens of this 
species, which was described from the Waldron beds at Waldron, Ind., and hitherto has not 
been recorded from any other horizon or locality. The Waldron specim< ns show a .-light 
variation in the shape of the celluliferous side, this being either angular along a central line, 
or rounded. The specimens from New York exhibit only an angulated obverse. This angu- 
lation is a good specific character, the rounded obverse being only a feature of the aged con- 
dition. "Compared with P. diffusa, this species, in addition to having the character just 
mentioned, is distinguished by having the reverse marked with 3 to 5 granulose striae, 
instead of 6 to 8, in the width of a branch, and by an obverse side with 3 to 4 ranges of 
more rounded zocecia. P. niagarensis has not the graceful method of growth pertaining to 
D. diffusa and is a less handsome species in every respect. 
The specimen figured by Hall as Fenestella (n. sp.) on PI. 40D, fig. 4, of Nat. Hist. New 
York, Pal. II, proves to belong to this species. 
Occurrence. — Not uncommon in the Rochester shale at Lockport and Niagara Falls, N. \ ., 
and in the Waldron shale at Waldron, Ind. 
Catalogue number, 35742, U. S. National Museum. 
