1879.] NATURAL SCIENCES OF PHILADELPHIA. 45 



marly limestone of Niagara period, north side Beargrass Creek, 

 one mile east of Louisville, Jefferson County, Ky. 



I have two excellent specimens with both valves united ; also 

 ten good ventral valves of this species. 



Calceola attenuates, V. W". Lyon, n. sp. 



Shell thick, attenuated, valves not articulated ; area of ventral 

 valve high and narrow, curving to the right, then to the left, then 

 to the right (some have three curves, others only two) ; area 

 straight part of the distance from the aperture toward the apex, 

 then curving gradually upward and outward (some specimens 

 have two curves upward, others one) ; area two inches high, with 

 an obscure central line; hinge three-tenths inch wide, straight. 



Markings of growth in some specimens very prominent, also 

 striae extending around the shell, parallel to the semicircular 

 opening or mouth. One of the most remarkable features of this 

 species is, that along the outer edge, and sometimes the central 

 line of the area, at almost each line of growth, and also in one or 

 two specimens at the mouth of the shell, are one or more pro- 

 cesses or small bodies having the appearance of foot-stalks. Some 

 of them are one-tenth inch in length, others four-tenths. At first 

 I thought these processes had served merely to attach the shell 

 to some permanent body ; but after cleaning one very large and 

 elegant specimen, I discovered these processes to be young Cal- 

 ceolee, showing all the distinct features of the older one. 



In one young ventral valve, which is attached to the second 

 line of growth of an adult, the cardinal process or tooth is perfect. 



Another most singular feature in the adult of this species is, 

 that in two places the central line of the area is lifted at the line 

 of growth, and the cardinal process is seen at each. This speci- 

 men has the appearance as if three adults had almost swallowed 

 each other, leaving onty the hinge lines and tooth visible. Cardi- 

 nal process three-tenths inch long, from two to three lines wide, 

 round and smooth along its summit, gradually diminishing in 

 width towards its end, not reaching the end of the cavity. In 

 some specimens the process is larger and longer than above indi- 

 cated, but it never reaches the bottom of the cavity as in C. cor- 

 niculum. The characters of this species are so well marked that 

 it can be distinguished at a glance from any known species of 

 Calceola. 



