126 Morgan Expeditions. 



is readily distinguished from P. sulcata, by the regular 

 curvature of the surface from the anterior to the posterior 

 end, and by the absence of a sinus. 



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

 Brazil; associated with Spirifera Pedroana, etc. 



Genus TENTACULITES, Schlotheim. 

 Tentaculites Eldredgianus, sp. now 



Shell small, rather long, straight, circular in cross-section, at least l mm 

 in diameter at the larger end, and tapering very gradually to an acute 

 point. Length of the most perfect specimen, a fragment, about 16 mm . 

 Annulations narrow, quite prominent, and angular or slightly rounded 

 on the summit; the interspaces are generally about twice as wide as 

 the annulations, though they vary somewhat in width, and are flattened 

 or a little rounded in the bottom ; they are ornamented by line annular 

 raised lines, of which there are about four or Ave in each interspace, 

 near the larger end of the specimen. The annulations decrease in size, 

 but become more numerous toward the apex. There are about 5 to 7 

 in the space of 3 mm near the large end. 



The specimens of this species, so far obtained, are from 

 the sandstone, in which they exist as moulds of the exterior 

 surface, generally filled up with clay or sandy material. 

 The moulds usually preserve the impression of the annu- 

 lations very sharply ; the annular raised lines, however, 

 are seldom preserved. The casts formed by the filling up 

 of the moulds are never exact copies, but in them the an- 

 nulations are almost always low and rounded. The full 

 length is not preserved in any of the specimens obtained, 

 but it was probably not much greater than 16 lm ". Although 

 the distance between the annulations varies, the variation 

 is never very great, and is generally regular through the 

 same specimen, the interspaces becoming gradually narrower 

 toward the apex. 



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

 of Para, Brazil ; associated with Spirifera Pedroana, etc. 



