124 Morgan Expeditions. 



This form of Modiomorpha, which is quite abundant at 

 Erere, although very constant in its outline, varies consid- 

 erably in its surface characters, as described above. The 

 specimens obtained are all moulds of the interior and ex- 

 terior. Associated with JSfuculites JVyssa, Spirifera Pedro- 

 ana, etc., in the Devonian sandstone of Erere, Prov. of 

 Para, Brazil. 



Named in honor of Senhor Pimenta Bueno of Para, to 

 whom the expeditions are under obligations. 



Genus PAL^ANEILO, Hall. 



Palseaneilo sulcata, sp. nov. 



Shell of moderate size, elongate, slightly gibbous, and apparently sub- 

 elliptical in outline, with the height less than two-thirds the length. 

 Dorsal margin inclining slightly downward in extending backward from the 

 beaks. The anterior margin appears to be slightly concave, for about one- 

 third its length from the beaks, and forms an angle of nearly 120° with 

 the dorsal margin; in its lower two-thirds it is well and regularly 

 rounded. Ventral margin nearly straight and suddenly indented toward 

 the posterior extremity of the shell, which Is imperfect in all the speci- 

 mens of this species yet obtained. Beaks situated at a distance from the 

 front, equal to d»little less than half the height of the shell, quite prom- 

 inent and incurved to the hinge line. The valves are most convex just 

 above and anterior to the middle, with the surface arching quite strongly 

 and regularly, the curvature, however, increasing somewhat in strength, 

 from the ventral margin to the beaks. A rather deep and well marked 

 sinus commences in each valve on the posterior side of the beak, where 

 it is very small, and extends obliquely across the valve to the ventral 

 margin, near the posterior extremity of the shell, increasing gradually in 

 size at the same time, the margin being deeply indented by it. The an- 

 terior edge of the sinus is quite abrupt and forms a slight fold on the 

 surface of the valve ; it makes an angle of about 30° with the dorsal 

 margin of the shell; the posterior edge rounds over gradually. From 

 the anterior margin of the valve the surface rounds up gradually for a 

 short distance, and then extends with very little curvature to the sinus. 

 Surface of mould smooth. Length, about 17 mm ; height, 11-5 mm ; depth 

 of each valve, 3-5 mm . 



This species of lamellibranch has the external characters 

 of the genus Palceaneilo, but the specimens representing it 

 are not in a condition to show the character of the hinge, 





