PART I CHAZYAN AND RELATED BRACHIOPODS—COOPER 561 
row fold, rather than recalling any members of the Camerellidae. Among the 
latter the transverse form is suggestive of Parastrophina, but usually the brachial 
valve of that genus is proportionately much deeper and more swollen than the 
pedicle valve. In these respects it is thus quite unlike Brevicamera. 
Although the exterior of Brevicamera is not unusual, the interior characters 
are, especially those of the brachial valve. The spondylium of the pedicle valve 
presents no unusual features. It is small and narrow at the front, and the dental 
plates are short. Actually the whole structure is fairly small when compared to 
some other genera such as Camerella itself. The median septum is short and 
does not extend anterior to the spondylium. In this respect the genus is unlike 
most related genera. If one can judge by genera at the summit of the syntrophid 
line and of the Gypidulinae, abbreviation of the septum is an advanced charac- 
ter which appears late in a lineage. 
The brachial valve is the one which gives definition and focus to the genus be- 
catise no camerellid like it is known. The entire cardinalia are of interest. The 
brachiophores are short but somewhat bulbous opposite the socket. At this point 
they have a small process, directed obliquely toward the opposite valve, which 
must serve as an accessory articulating nub. The socket is defined in part by a 
small fulcral plate. The blade of the brachiophore is short and cresentic in sec- 
tion. Brachiophore plates are subparallel and extend nearly vertically to the floor 
of the valve where they join a callosity to form a sessile cruralium. The anterior 
end of the callosity is extended anteriorly to divide the small and confined muscle 
field into two parts. The sessile cruralium is quite unlike the brachial structure 
of any known genus although loss of median septum occurs in the peculiar genus 
Plectocamara. 
Specimens of Brevicamera so far have been found only in the Pratt Ferry ex- 
posures in Alabama, and here they are rare indeed. 
BREVICAMERA CAMERATA Cooper, new species 
Plate 118, A, figures 1-10; plate 119, FE, figures 15, 16 
Small, transversely elliptical in outline; sides oblique, straight, forming an 
apical angle of about 120°. Sides narrowly rounded; anterior margin nearly 
straight. Valves convex, the brachial valve slightly deeper than the pedicle valve. 
Anterior commissure narrowly and steeply uniplicate. Surface smooth except 
for the anterior margin which is marked by a few costae, 2 on the flanks, 3 or 
4 on the fold, and 2 in the sulcus, the latter confined to the tongue. 
Pedicle valve gently convex in lateral profile but with the maximum curvature 
in the posterior half; anterior profile broadly and gently convex. Umbonal re- 
gion narrowly swollen; median region inflated. Sulcus originating abruptly at 
the middle, fairly wide, deepening rapidly. Tongue geniculated at a right angle, 
long, narrow, and truncated at the front. Flanks bounding sulcus marked by a 
strong plica that extends indistinctly for some distance in a posteromedian di- 
rection. Flanks inflated and with steep slopes. Interior with short, narrow, and 
delicate spondylium. Interarea nearly obsolete. 
