24 SIXTEENTH REPORT ON THE CABINET OF NAT. HISTORY. 



" LINGULA MELIE ( n. s.)." 



Shell elliptical ; length and breadth about as three to two, the 

 width often a little greater ; moderately convex, the umbo 

 prominent, and below it begins a narrow flattened space, w^hich, 

 very gradually widening, reaches to the base ( this feature is 

 noticed on the ventral valves). Sides curving, the margins flat- 

 tened or a little recurved. Beak of the ventral valve extended 

 and acute ; and in partially exfoliated specimens there is a 

 depressed sublinear area reaching more than one-third the 

 length of the shell, and margined on each side by a sharp line. 



The specimens, which appear to be the ventral valves of the same 

 species, are obtuse at the cardinal extremity, and proportion- 

 ally wider towards the base. The most extreme example of this 

 kind is shown in fig. 3, while 4 is the extreme of the other form. 



The surface characters are the same in all the specimens, and, on 

 the exterior shell, consist of fine concentric stride which are 

 crowded at intervals into ridges, giving an undulating surface. 

 On the exfoliated fossil, the concentric wrinkles are preserved 

 with faint impressions of the striae 5 and obscure radiating 

 coarser striae mark the surface, becoming stronger towards the 

 margins, and terminating just within the edge in minute de- 

 pressions or puncta. 



This species, in some of its forms, resembles the L. spatulata, but is 

 larger, and also very distinct in the details of its surface markings. 



This species occurs at Chagrin falls, Ohio, in strata of the age of the 

 Chemung group. 



" LINGULA CUYAHOGA (n.s.).'^ 



Shell subelliptical ; length and breadth about as five to three ; 



sides nearly parallel, narrowing a little towards the cardinal 



margins ; beak obtuse ; cardinal slopes very little inclined j 



base abruptly rounded. 

 Surface marked by fine concentric strise, and, on the exfoliated 



surface, by fine obscure radiating strise. 



A single valve (ventral?) is very convex along the middle for 

 two-thirds of the length ; the front rather depressed, and the 

 entire margin, from the cardinal extremities, flattened. This 

 specimen is in sandstone. Another imperfect specimen in soft 

 shale has nearly the same proportions, but is flattened, and the 

 cardinal slopes less nearly rectangular to the axis. 



