194 Report oF THE STATE GEOLOGIST. 
and terminates at the junction of the lateral branches in a short, 
horizontal process. 
External surface of the valves covered with numerous radiat- 
ing plications; occasionally smooth. Shell-substance fibrous, 
impunctate. 
Type, Unceites gryphus, Schlotheim (sp.). Stringocephalus 
limestone (Middle Devonian). 
Uncinella, Waagen. 1883. 
(Plate 87, figs. 28-25.) 
Shells with a general external resemblance to Rerzra. The 
valves are more or less finely plicated; no sinus or median fold 
developed; the hinge-line is curved; the beak full and strongly 
incurved, provided with a distant deltarium ; apex truncated by 
a large oval foramen. 
The shell bears spirals of the same general disposition as in 
Rerzia or Uncrres, but neither the jugum nor the mode of junc- 
tion of the primary lamellz with the crura is known. In the 
pedicle-valve below the apex of the beak, there is an excavated, 
small but very distinct deltarium ; its composition of two pieces 
@ 
Fia. 362. Fig. 363. 
Interior cardinal region of pedicle- and brachial valves of Uncinella indica, Waagen. (WAAGEN. 
has not, however, been made out. It does not reach to the hinge- 
line, but is cut out below for the reception of the apex of the 
small valve. Hinge-teeth long and not supported by dental plates. 
In the brachial valve the apex is flattened, and no cardinal 
process is present. At the apex two sharp ridges take their 
origin, limiting the dental sockets on the other side. These latter 
are elongated, deep, triangular. There is no hinge-plate, but the 
crura take their origin immediately at the apex, sloping strongly 
toward the middle line, and very nearly reaching the bottom of - 
the valve. 
Type, Uncinella indica, Waagen. 
Distribution. Carboniferous. 
46 
