274 NEW YORK STATE MUSEUM 



tatives of the genus, but its aviculoid characters are not altogether clear. 

 There is a certain pterineoid aspect in the right valve due to the develop- 

 ment of a posterior flange, but this seems to us hardly homologous with the 

 wing of the Aviculidae, as it is a broad flaring arched surface bounding a 

 wide open posterior aperture, extending from beak to margin. Here, how- 

 ever, analogy is imperfect, as ; t is evident that there was no corresponding 

 surface on the left valve. This condition seems to be displayed by some of 

 the figures given by Freeh of pyrite casts of conjoined valves from Nehden. 1 

 Habitat. Genesee province ; Chautauqua subprovince. In the soft 

 arenaceous shales at Forestville, Chautauqua co., and Gowanda, Cattaraugus 

 co. In the German Devonic the species is restricted to the higher marine 

 Upper Devonic at Oberscheld, in the Clymenia limestone of the Enkeberg 

 and in the shales with G o n i a t i t e s curvispina at Nehden. 



Loxopteria laevis Freeh 



Plate 14, fig. 1-7 



Kochia (Loxopteria) laevis Freeh, Die Devonischen Aviculiden Deutsch- 

 lands; Abhandl. z. geolog. Specialkarte Preuss. u. d. Thiir. St. 1891. v. 9, Heft 3, 

 p. 76, pi. 6, fig. $-$£ 



Shell subtriangular, general surface depressed. Left valve with much 

 the same outline as L. d ispar, less convex in the umbonal region. Poste- 

 rior margin or umbonal ridge with gentle outward curve specially in the 

 umbonal region. Anterior margin at first incurved beneath the beak then 

 bending outward and rounding to the base, which is transverse, with a broad 

 sinuous upward bend toward the first lateral angle. The right valve differs 

 from that of L. d i s p a r in the notable depression of the beak and umbo. 

 The larval shell itself is concave, and the umbonal area all about it is 

 depressed and curved downward toward the hinge, and this depressed area 

 extends obliquely backward, covering the greater portion of the valve. 

 It is bounded in front by a low convex area with an abrupt marginal 

 slope, incurved toward the beak, and behind it curves upward to a pretty 



1 Op. cit. pi. 6, fig. 4, 4a. 



