Rathbun.] 18 [May 15, 



The markings of the shell are indistinctly preserved in the single 

 specimen I have examined; they appear to consist of short, low, 

 rounded, radiating, raised lines, which are narrower than the inter- 

 vening spaces. They are of variable lengths — one-eighth to one-sixth 

 that of the valve, or more — and some appear to extend the entire 

 length of the valve. They are more or less regularly distributed, 

 and the anterior end of each line is slightly elevated, as though it 

 had formed the base of a spine. The bases of two or three small 

 spines are preserved near the right cardinal angle. Length and 

 breadth of shell each about 9.5 mm. 



Having only one specimen of this form, it is impossible to de- 

 termine to what described species of Productella it may be the 

 most closely related. The number of species of Productella de- 

 scribed from the Devonian of North America is so large, that it is 

 probable the form under discussion may ultimately fall into one of 

 them. It bears a certain resemblance to several of Hall's species, 

 more particularly P. navicella of the Corniferous limestone and Ham- 

 ilton group of New York. 



Devonian sandstone of the Rio Maecurii, Pari. (Geol. Comm., 

 1876.) 

 Chonetes Comstockii Hartt, MS.^ 



Rathbun, Bull. Buff. Soc. Nat. Sci., i, no. 4, p. 250, pi. ix, 1874. 

 Devonian sandstone, Erere. (Morgan Exs., 1870 and '71; Geol. 

 Comm., 1876.) Rio Maecurii. (Geol. Comm., 1876.) 



This species is of very common occurrence at Erere, but only three 

 small specimens were obtained from the Rio Maecurii. 

 Chonetes Freitasii, sp. nov. 



Shell usually quite strongly concavo-convex, and varying in out- 

 line from longitudinally serai-elliptical to transversely sub-elliptical 

 or oblong; proportions of length to breadth as 6 to 7, 5 to 6, 3 to 4 

 or 2 to 3. Hinge line straight and, in the majority of cases, equalling 

 the width of the shell or more. Cardinal extremities forming right 

 or acute angles, and often much extended in sharp, mucronate points; 

 but trequently the hinge line is shorter than the width of the shell, 

 and the cardinal extremities are then obtusely angular or regularly 

 rounded. Where the length of the hinge line equals the width of the 



1 Bj- an oversight in the original paper on the Devonian Bracliiopoda of Erer6 

 (loc. cit.), I omitted to state that the names of the species therein accredited 

 to Professor Hartt were taken from his manuscript notes. 



