NAPLES FAUNA IN WESTERN NEW YORK, PART 2 3 I 5 



ueptodomxts McCoy. 1844 

 Leptodomus interplicatus sp. nov. 



Plate 12, fig. 32-34 



Though specimens of this species are not well preserved, they have 

 proved rather common at one horizon in the Naples subprovince and show 

 quite distinctive sculpture features. The shells are rather below medium 

 size for the genus, were transversely ovate in outline, widening posteriorly 

 and thence narrowing to the extremity. Beaks anterior and arched over 

 the hinge. Surface concentrically plicate or rugose on the anterior slopes. 

 These plications are simple near the extremity, but over the middle slope 

 they narrow and bifurcate or receive others of equal size in the intervals. 

 Passing backward both sets become rather abruptly obsolete and merge by 

 twos or threes into broad obscure wrinkles on the posterior slope. The 

 last, again, become wholly obsolete on the extremital surface, leaving it 

 quite smooth. The oblique median umbonal furrow on the shell is quite 

 obscure. The species may be compared in some respects of size and sur- 

 face with L. arcuatus Conrad of the Hamilton shales, but the features 

 described render it distinct. 



Dimensions. An average shell has a length of about 30 mm and a 

 hight of 20 mm. 



Habitat. Genesee province ; Naples subprovince. In the higher 

 (Hatch) shales at Naples. 



Leptodomus multiplex sp. nov. 



Plate 12, fig. 30 



This shell differs from the foregoing and other species of the genus in 

 a transversely elongate and narrow form, rather long, straight hinge, sub. 

 truncate posterior extremity and transverse basal margin. The beak is 

 anterior, and a low oblique median sulcus traverses the shell from beak to 

 base. The markings of the surface consist in narrow concentric plications 

 of subequal size over the body of the shell, and these are divided by the 

 sulcus, where for a short distance all become obsolete. In front, and over 



