14 



The yolk is of large size. In the development of the legs, 

 these are seen to be formed distinct from the vertebral column, 

 so that, morphologically considered, they cannot be called ap- 

 pendages of the spine. The external branchiae are developed 

 and disappear at a very early period. The tail is fully formed 

 in the embryo, but afterwards is absorbed, so that when the ani- 

 mal escapes from the egg the latter has disappeared. 



Prof. Wyman exhibited the embryos in three stages of devel- 

 opment, and a section of the back of the female. The fully 

 formed embryo is larger than the original egg, so that the ani- 

 mal must have absorbed something from the pouch in which it 

 was lodged — a fact in the embryology of batrachians entirely by 

 itself. 



Prof. W. B. Rogers exhibited a series of fossils from the 

 middle secondary belts of North Carolina, Virginia, Penn- 

 sylvania, and Massachusetts ; chiefly, he said, with the view 

 of calling attention to the evidence afforded by some of 

 them, of the close relation in geological age between what 

 has been called the New P^ed Sandstone of the Middle 

 States and Connecticut Valley, first designated by Prof. 

 H. D. Rogers as the Mi'Qdle Secondary Group, and the coal 

 bearing rocks of eastern Virginia and North Carolina. 



Prof. R. referred to the existence in Virginia of three distinct 

 belts of these rocks. The most eastern of these, extending 

 almost continuously from the Appommatox River to the Potomac, 

 includes the coal-fields of Chesterfield and Henrico Counties. 

 The middle tract, about twenty-five miles west by south of the 

 preceding, is of much less extent, and has not yet furnished any 

 workable coal seam. Somewhat intermediate in trend to these 

 is a belt of analogous rocks in North Carolina, commencing* 

 some distance south of the Virginia line and stretching south- 

 westwardly across the State, and for a few miles beyond its limits, 

 into South Carolina. This area, first mapped by Prof. Mitchell, 

 includes the coal bearing rocks of Deep River. The western 

 belt extends, with two considerable interruptions, entirely across 

 Virginia, being prolonged towards the southwest in the course of 



