FENESTELLID.E. 53 
LOCULIPORA ULRICHI n. sp. 
PL XXI, fig. 2; PL XXV, figs. 22-24. 
Compared with the Waldron species, L. ambigua Hall, this new form presents the follow- 
ing differences. First, the form of the zoarium, especially the basal portion, differs in that it 
is much narrower, is stalk-like, and expands much more slowly; second, the reverse side of 
the zoarium is less distinctly papillated; third, the obverse side is more regularly and con- 
stantly striated; fourth, the fenestrules on the obverse (outer) side are more regular and 
quadrate in form; fifth, the apertural rim of the zooecia is less developed; and sixth, the 
zoarium as a whole is a trifle less robust. The stalk-like form of the zoarium, the regularly 
striated obverse side, and the quadrate form of the fenestrules are the most obvious features 
and will readily prevent confusion with related species. 
Tangential sections of L. ulrichi show that the apertural rim is so little developed that it is 
scarcely distinguishable, but, in similar sections of L. ambigua the rim is a very conspicuous 
feature. Compared further L. ulrichi has smaller fenestrules, 8 occurring in 5 mm., meas- 
uring lengthwise, and 10 in the same space transversely, while in L. ambigua 6 and 9 occur 
respectively in the same spaces. 
The other Silurian species, L. gothlandica Ulrich, from the island of Gotland, is also related, 
but differs in that its fenestrules are smaller and less quadrate and the zoarium expands 
more rapidly. 
This fine species is named in honor of Dr. E. O. Ulrich of the U. S. Geological Survey, to 
whom the writer is indebted for valued suggestions and help in the preparation of this paper. 
Occurrence. — Lockport, Lewiston, Niagara Gorge, and Rochester, N. Y.; Grimsby and 
Thorold, Ontario. 
Catalogue numbers, 35548, 35765, 35766, U. S. National Museum. 
LOCULIPORA AMBKiiTA Vai\ PRECURSOR U. Vill . 
Compare Loculipora ambigua (Mall), Twenty-eighth Ann. Rept. New York State Mus. (doc. ed.), 1876, 
pi. 11, figs. 17-21; (Mus. ed.) 1879, p. 123, pi. 11, figs. 17-21; Eleventh Ann. Rept. Indiana Geol. Nat. 
Hist., 1882, p. 248, pi. 11, figs. 17-21. 
This subordinate name is proposed to distinguish a form of Loculipora found rather rarely 
in the Rochester shale at Lockport, and in the corresponding Osgood beds at Osgood, Ind. 
All of the specimens so far seen agree with L. ambigua in size and in having an obtusely 
conical zoarium with comparatively irregular branches and fenestrules. The reverse side 
of the branches is granulo-striate, agreeing in this respect with young specimens of L. 
ambigua, but the zooecial apertures of the proposed variety are scarcely so much elevated as 
in the typical form of the species. Better material perhaps might show reasons for consider- 
ing this a distinct species, but at present it seems best to consider it only an early variety of 
the Waldron form. 
Occurrence. — Apparently rare in the Rochester shale at Lockport, N. Y., and in the 
Osgood beds at, Osgood, Ind. 
Catalogue numbers, 35554, 35555, .U. S. National Museum. 
Genus THAMNISCUS King. 
Zoarium as in Polypora, but branches bifurcate more frequently and are rarely or not at all 
connected by dissepiments. 
