GASTROPODA. 851 
Bucanitda.] 
TYPICAL SECTION. 
B. sulecatina Emmons. Chazy. B. sublata U. & S. Stone’s River group. 
B. halli U. & S. Stones Riy. and Black Riv. grs. B, rugatina U. &S. Black River group. 
B. emmonsit U.& S. Stones Riv. & Black Riv. grs. B. elliptica U. & S. Trenton group. 
B. minnesotensis U. &S. Stones Riv. & Blk Rv. grs. B. intertexta Hall. Trenton group. 
? B. punctifrons Emmons. Trenton group. 
Foreign species.—B. ozekanowskiz Schmidt, Lower Silurian, Russia. 
B. NASHVILLENSIS SECTION. 
BL. nashvillensis Ulrich. Trenton group. B. peracuta Ulrich. Trenton group. 
BL. lindsleyi Safford. Trenton group. B. singularis Ulrich. Trenton group, 
B. frankfortensis Ulrich. Trenton group. B. nana Ulrich. Trenton group. 
5, subangulata Ulrich. Trenton group. B. nana, var. subpatula Ulrich. Trenton group. 
B. micronema Ulrich. Trenton group. B. simulatriz Ulrich. Richmond group. 
B. crassa Ulrich. Richmond group. 
SaLprnegostoma, Roemer. (Leth. Geognostica, 1876.) Shell symmetrically coiled 
in one plane; volutions numerous, enlarging gradually, scarcely embracing, the 
consequence beinga large open umbilicus. Aperture abruptly expanded at maturity, 
trumpet like; peristome thin, the outer portion slightly sinuate. Inner volutions 
with a slit band as in Bucania. This is replaced in the outer half of the last whorl 
by a long narrow opening or slit which, however, does not extend to the apertural 
expansion, but is closed some distance behind it. Surface marked with simple or 
sublamellose lines of growth and more or less oblique, irregular and sometimes 
interrupted or wavy revolving lines. Type, S. megalostoma Kichwald sp. 
AMERICAN SPECIES. 
S. buelli Whitfield sp. Stones River group. S. imbricata U. & S. Richmond group. 
S. buelli, var. kentuckiensis Ulr. Black Riv. group. 8S. richmondensis Ulr, Richmond group. 
S. expansa Hallsp. Trenton group. S. canadensis Billings. Hudson River group. 
S. sculptilis U. & S. Trenton group. S. fraternus Billings. Hudson River group. 
EUROPEAN SPECIES. 
S. megalostoma EKichwald. Lower Silurian. S. locator Kichwald sp. Lower Silurian. 
S. compressa Hichwald sp. 
Tremanotus, Hall.* In all respects like Salpingostoma excepting that an 
expanded aperture is developed at frequent and regular intervals, and the dorsal 
sht closed at corresponding periods, so that, instead of a continuous long opening, 
there is a series of small, elongate elliptical perforations. Type, T. alpheus Hall. 
AMERICAN SPECIES. 
T. alpheus Hall. Niagara group. T. trigonostomu Hall & Whitfield. Niagara group. 
T. chicagoensis McChesney sp. Niagara group. T. angustata Hallsp. Niagara. 
T. profunda Conrad sp. Lower Helderberg group. 
FOREIGN SPECIES, 
T. longitudinalis Lindstrom. Up. Silur., Gotland. T. compressus Lindstrom. Up. Silur., Gotland. 
T. maideni Etheridge, Jr. ? Triassic, New South Wales. 
ConRADELLA, n. gen. (Phragmolites, Conrad, 1838, Ann. Geol. Rep. New York, 
p. 119.) Shell coiled symmetrically, general form as in Cyrtolites and Oxydiscus, the 
volutions enlarging gradually and being strongly keeled dorsally. Aperture oval or 
* Twentieth Rep. New York St. Mus, Nat. Hist., p. 347; 1868, 
