Morgan Expeditions. 125 



which is crenulated in that genus. Only a few specimeus 

 have been obtained. 



From the Devonian sandstone of Erere, Prov. of Para, 

 Brazil ; associated with Streptorhynchus Agassizii, etc. 



Palseaneilo ? simplex, sp. nov. 



Shell of medium size, elongate, quite regularly sub-elliptical iu outline 

 and of moderate convexity ; height about two-thirds the length. Anterior 

 margin not quite as high as the posterior; both anterior and posterior 

 margins regularly and quite strongly rounded, and passing gradually into 

 the ventral margin, which is regularly and moderately rounded. The 

 dorsal margin is nearly straight and extends directly backwards from the 

 beak; its length is less than one-half that of the shell. Beaks situated 

 at about one-third the length of the shell from the anterior end, quite 

 small, rather strongly incurved to the plane of the hinge, and slightly 

 elevated above the hinge margin, with the apices acute. The point of 

 greatest convexity of the valves is just above the middle. The curvature 

 of the surface from the ventral margin to the beaks is moderate and 

 nearly regular, growing gradually stronger, however, toward the beaks. 

 The curvature along the antero-posterior diameter is quite moderate and 

 regular, the slopes toward the anterior and posterior mai'gins from the 

 middle being sub-equal. Toward the dorsal margin the slope is moderate 

 posteriorly, but grows gradually stronger as the beaks are approached, 

 just behind which it is very abrupt. Immediately in front of the beaks 

 the surface is slightly concave. Surface markings unknown ; the surface 

 of the internal moulds is quite smooth. Length, 16 mm ; height, 12 mm ; 

 depth of single valve, 3 mm . 



The above description of this form was made from a 

 single, very perfect specimen, an internal mould of the 

 left valve, in which, however, the characters of the hinge 

 are not preserved. The generic relations of the species 

 are thus rendered doubtful ; but it agrees externally with 

 Prof. Hall's genus Paloeaneilo in which we place it pro- 

 visionally. Besides the single specimen just mentioned, 

 there are four or five other specimens of lamellibranchs 

 from Erere, which apparently belong to this same species. 

 In them the beak is sometimes more acute, and the curva- 

 ture of the surface varies slightly. In all the other char- 

 acters they agree quite perfectly. This form of Palceaneilo 



