642 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 127 
ROSTRICELLULA NUCLEOLATA Cooper, new species 
Plate 135, D, figures 16-25 
Shell small for the genus, somewhat globular, slightly wider than long. Pos- 
terolateral margins short and straight, sides moderately rounded; anterior mar- 
gin broadly rounded. Apical angle slightly less than 100°. Costae elevated and 
narrowly rounded, numbering 4 on the fold, 3 in the sulcus, and 4 on the flanks. 
Pedicle valve gently convex in lateral profile and nearly flat in anterior pro- 
file; umbonal region convex and somewhat swollen; sulcus broad and shallow, 
originating 5 mm. anterior to the beak which is strongly incurved. Tongue short, 
not strongly geniculated. Flanks narrowly rounded and steep. 
Brachial valve slightly deeper than the pedicle valve, evenly and gently convex 
in lateral profile, broadly and flatly convex in anterior profile but with precipitous 
sides. Umbonal region gently sulcate ; fold low, slightly elevated above the flanks 
at the anterior end. Flanks narrowly rounded and steep-sided. 
Measurements in mm.—Holotype, length 9.3, brachial length 8.4, width 10.0, 
thickness 7.0. 
Types.—Holotype: 48984a; unfigured paratypes: 48984 (unlettered). 
Horizon and locality.—Platteville formation (lower buff = Pecatonica member) 
in Minnesota: At Minneapolis. 
Discussion.—Small size and rotund form characterize this species. Its nearest 
relative is R. minnesotensis from which it differs in size, rotundity, and a wider 
fold and sulcus. 
ROSTRICELLULA ORIENTALIS (Billings) 
Plate 129, G, figures 26-32; plate 135, C, figures 11-15; plate 137, 1, figures 61-65 
Rhynchonella orientalis B1Lttncs, Canadian Nat., vol. 4, p. 443, fig. 21, 1859.—Locan, Geol. 
Canada, p. 126, fig. 57, 1863. 
Camarotoechia orientalis (Billings) RAymMonp, Ann. Carnegie Mus., vol. 7, No. 2, p. 223, 
pl. 33, figs. 32, 33, I91I.—TWENHOFEL and Waitin, Geol. Soc. Amer. Special Pap. 11, 
p. 51, pl. 7, figs. 22-24, 1938. 
A small shell frequently misidentified. The writer has seen few authentic ex- 
amples of this species outside of the Mingan Islands. The specimens from 
St. Martin Junction, Quebec, identified as this species by Raymond are herein 
referred to a new species, R. raymondi. The one specimen of this species from 
Aylmer, Quebec, in Raymond’s lot has the size and ornamentation of R. orien- 
talis but is too crushed to make the identification positive. The species is not 
reported from New York. 
Types.—Figured hypotypes: 111489, 111490a; G.S.C. 2184. 
Horizon and locality—Mingan formation, Mingan Islands, St. Lawrence 
River, Canada. 
ROSTRICELLULA OVATA Cooper, new species 
Plate 131, E, figures 33-39; plate 133, E, figures 27-35 
Shell of about medium size, triangular in outline with the length and width 
nearly equal. Greatest width anterior to the middle; sides long and straight 
