36 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 134 
Measurements in mm.—Holotype, length 34.7, width at middle 46, 
hinge width 44+, surface length 56, thickness through middle of 
visceral area 8.5, height 14. 
Types.—Holotype, U.S.N.M. 125327; figured paratype, U.S.N.M. 
125320. 
Localities —638; P10; S43, S46, S47, S51, S67, S103; U.O. 
2202-2, 2204-3. 
Discussion——This species is characterized by its wide hinge, the 
big ears, and deep sulcus, although this last feature is somewhat 
variable. Few described species of Antiquatonia from the Permian 
are available for comparison. 
Antiquatonia planumbona Stehli from the Bone Spring formation 
in the Sierra Diablo, Texas, is sulcate but not so deeply as the Oregon 
species. The Texas shell is also more finely reticulate than the Oregon 
species. 
The holotype of Productus hessensis King is a poorly preserved 
specimen, but nevertheless shows the elevated ridge characteristic of 
Antiquatonia. It is also a sulcate form but is a larger and more finely 
ornamented species than A. sulcata. 
Productus semireticulatus arcticus Whitfield is a deeply sulcate 
species similar to the Oregon form but it is not certain to what genus 
it belongs. In any case, the type as illustrated by Whitfield is a 
narrower species than the Oregon Antiquatomia. 
PROBOSCIDELLA? CARINATA Muir-Wood and Cooper, new species 
Plate 3B, figures 10-17; text figure 2B 
Specimens rare, showing the pedicle valve only in a hard matrix; 
small, with the hinge forming the widest part; length less than the 
width. Pedicle valve with visceral area slightly wider than long. Semi- 
circular in lateral profile, more broadly arched in anterior profile; 
beak narrow, protruding posterior to the hinge; umbonal region nar- 
rowly swollen; sulcus originating about 5 mm. anterior to the beak, 
shallow and narrow, terminating in a trough 9 to 12 mm. (surface 
measure) from the beak. Visceral region marked by radiating cos- 
tellae cancellated by concentric undulations. Trail moderately convex 
in lateral profile, separated from the visceral area by a slight periph- 
eral depression ; trail anterior to median troughlike depression nasute 
and carinate ; flanks of trail moderately convex and descending nearly 
vertically from the visceral area. Trail ornamented by costellae. 
Brachial valve closely fitting the concavity of the pedicle valve 
interior, as seen in longitudinal section, otherwise unknown. 
