1887.] natural sciences of philadelphia. 49 



February 15. 



Mr. Geo. W. Tryon Jr. in the chair. 



Twenty-four persons present. 



Grampus Rissoanus on the American Coast. Pi'of. Heilprin 

 called attention to the recent stranding on the New Jersey coast, at 

 Atlantic City, of Risso's whale. Grampus Rissoanus, a form readily 

 distinguished from other allied cetaceans by the peculiar slaty 

 lines which are irregularly distributed over the body. The speaker 

 thought that this was the first instance of this singular Mediterranean 

 species having been recorded from the trans- Atlantic waters, and 

 emphasized the difficulty of drawing lines of delimitation to the 

 oceanic faunas. The specimen in question was dark-slaty in color 

 on the sides, verging to black on the back and measured about 

 eleven feet in length. 



February 22. 



Mr. Charles Morris in the chair. 



Nineteen persons present. 



Origin of the Excretory System in the Earth-worm. Professor 

 Edmund B. Wilson, of Bryn Mawr, Pa., laid before the Academy 

 an account of his observations on the development of Lumbricus 

 olidus, calling especial attention to the remarkable similarity that 

 exists between the development of the nephridia and the origin of 

 the excretory system in the vertebrates. The gastrula is foi'med 

 by a process of invagination. Upon the establishment of the 

 germ-bands, they are found to be essentially similar to those of 

 Clepsine, ending behind in eight large cells, by the continued 

 division of which the bands increase in length as the embryo grows. 

 Two of these large cells are mesoblasts (giving rise to the dis- 

 sepiments, muscles and vessels) two are neuroblasts (giving rise to 

 the ventral nerve-cord), two are nephroblasts (giving rise to 

 the excretory organs)and two give rise to cells whose fate could not 

 be determined. From each of these cells a row of cells extends for- 

 wards on the ventral side of the body between the ectoblast and 

 entoblast. The rows are at first one cell wide, but are converted in 

 front into solid cords, several cells in thickness. The principal 

 interest of the development lies in the origin and fate of the rows 



