680 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 127 
Measurements in mm.— 
Length Width Thickness 
HiOlotype 1. ch sb sie Peas OWE sa eee: CUR e Mee 3.1 a7 r7 
Paratype... ,43aeoe? beens St Pee Sees B:1 2.6 1.8 
Types.—Holotype: 111412a; unfigured paratype: 111412b. 
Horizon and locality—Bromide formation (Pooleville member—O-oplecia 
gouldi zone) in Carter County, Okla.: At Rock Crossing of Hickory Creek, 
about center sec. ‘35, T. 5 S., R. 1 E., Criner Hills. 
In Murray County, Okla.: At the top of Bromide, small quarry east of road 
in center NW4 sec. 11, T. 11 S., R. 3 E.; middle of bed 2, Spring Creek, sec. 
17) D2 RE PWS siehtly nerth:ot the middletof sec. ‘32)-'T "2-5: Rene, 
2 to 3 miles northeast of Springer; 50 feet below the Viola, 4 miles west and 
2 miles south of Davis. 
Discussion.—This species is suggestive of P. nicolleti and also of P. rotunda. 
From the former it differs in not possessing the strong radial costae on the flanks 
and in having a much broader fold in the sulcus of the brachial valve. It differs 
from P. rotunda in its smaller size, less rotund profile, less circular outline, more 
prominently elevated fold of the brachial valve, and the anterior third less de- 
flected toward the pedicle valve. The front margin of P. loeblichi is less nasute 
than that of the Tennessee species and is generally sharply truncated anteriorly. 
PROTOZYGA MAGNICOSTATA Cooper, new species 
Plate 140, A, figures I-9 
Shell resembling P. costata but length and width nearly equal; widest at or 
near the middle; sides strongly rounded; anterior margin somewhat broadly 
rounded; anterior commissure faintly sulcate; surface paucicostate, 2 strong 
costae marking the sulcus, 3 on the fold, and 2 or 3 on the flanks. Median costa 
of fold usually depressed and corresponding with furrow between costae occupy- 
ing sulcus. Costae strong. 
Measurements in mm.— 
Length Width Thickness 
LOT QE MTG i Selivis anshtawid nin eotian statewide Taare cusses 4.0 3.9 fee 
Paratyne CT EACAR Dy vas wi siechs ahaldcrasan pia ptcaie 4.1 3.9 2.0 
Types——Holotype: 117245a; figured paratypes: 117245b, 118040. 
Horizon and locality—Bromide formation (Mountain Lake member—30 to 
34 feet below the top of bed 10) in Oklahoma: On Tulip Creek, SW4NW4NE}4 
sec. 25, T. 2.S., R. 1 E., Carter County; bed 7, Spring, Creek, sec. 17, T. 2 S., 
R. 1 W., Murray County. 
Discussion —This species suggests P. costata but differs in being more rotund 
in outline and having stronger, more sparsely placed costae. Furthermore, 
P. magnicostata differs in the arrangement of the costae on the fold of the pedicle 
valve, the median one of which is sunk below the bounding, outside 2. 
