46 PROCEEDINGS OF THE ACADEMY OF [1879. 



Position and Locality. I have sixty good ventral valves from 

 the ferruginous cla}' and marly limestone of the Niagara period, 

 one mile east of Louisville, Ky., north side of Beargrass Creek. 



I have no doubt that the young of G. attenuatns and of all 

 other species of the Galceolidse became attached immediately after 

 germination, to the inner surface of the rim of the mouth, and 

 remained in this position until they were large enough to support 

 themselves. Lines of growth upon these species are nothing 

 more or less than the margins of former mouths, which are almost 

 alwa3 T s obliterated in very old adults, but in one instance two of 

 these old mouths are seen, showing the hinge, also the central 

 cardinal process, as well as the new one, within all of these 

 mouths, are seen young specimens of Calveola attached, having 

 the general characters of the adult. In two instances one of the 

 vigorous young attached itself to the bottom of the cavity and 

 eventually killed the old one, and then took complete possession. 



I have one specimen of G. attenuatns two inches long (ventral 

 valve), three-tenths inch wide at hinge, within the cavity of which 

 stands another Galceola of the same species one and a half inch 

 long, three-tenths inch at hinge; the apex of smaller is attached 

 to the bottom of the cavity of the larger, and almost fills it ; the 

 cardinal process of larger is seen. 



