May 1, 1903.] 



SCIENCE. 



693 



The Evolution and Distribution of the 

 Proboscidea: Professor Heney F. Os- 

 BORN, of New Tork. 



A New Fresh-Water Molluscan Faunule 

 from the Cretaceous of Montana: Mr. 

 T. W. Stanton, of Washington. (In- 

 troduced by Professor W. B. Scott.) 

 This paper describes and discusses a col- 

 lection of invertebrate fossils from near 

 Harlowton on the Musselshell River, Mon- 

 tana, collected in 1902 by Dr. Farr and 

 Mr. Silberling, of the Princeton Univer- 

 sity expedition. 



The species are only six in number, but 

 with one exception each is represented by 

 abundant and well-preserved examples. Of 

 these two are referred to Vnio, two to 

 Goniobasis, one to Campeloma and one 

 to Viviparus. The study of these fossils, 

 in connection with their reported strati- 

 graphic position and a general discussion 

 of the early Cretaceous and late Jurassic 

 non-marine formations of the region, leads 

 to the conclusion that they are probably 

 from a horizon near the base of the Upper 

 Cretaceous, or possibly as low as the Lower 

 Cretaceous. 



Hints on the Classification of the Arthro- 

 poda, the Group a Polyphyletic One: 

 Professor Alpheus S. Packard, of 

 Providence. 



Anatomy of the Flosculariidce : Professor 

 Thomas H. Montgomery, Jr., of Phila- 

 delphia. 



The Earliest Differentiations of the Egg: 

 Professor Edwin G. Conklin, of Phila- 

 delphia. 



In the living eggs of fresh-water snails 

 important differentiations are recognizable 

 before the eggs begin to divide. Soon after 

 the formation of the polar bodies clear 

 non-granular protoplasm accumulates at 

 the animal pole and spreads down over the 



surface of the egg towards the opposite 

 pole. About three fourths of the surface 

 of the entire egg is covered by this clear 

 protoplasm, which gives this portion of the 

 egg a milky appearance, while about one 

 fourth of the egg surface at the vegetative 

 pole is not covered by this protoplasmic 

 layer and is bright yellow in color. These 

 two portions remain distinct throughout the 

 subsequent development of the egg, the 

 protoplasmic area giving rise to the ecto- 

 derm, the yellow one to the endoderm and 

 mesoderm. The germ layers are, there- 

 fore visibly outlined in the unsegmented 

 egg. In these eggs the type of asymmetry 

 of the adult snail (whether dextral or 

 simitral) is also predetermined, probably 

 while the egg is still in the ovary. The 

 chief axis of the future animal is also 

 marked out in the egg, and is probably to 

 be traced dii'ectly back to the egg of the 

 previous generation. In this case, there- 

 fore, these axial relations are probably con- 

 tinuous from generation to generation. 



Some Properties of Nichel: Mr. Joseph 

 Wharton, of Philadelphia. 



A Resume of the Composition of Petro- 

 leum from Different Fields: Professor 

 Charles F. Mabery, of Cleveland. 

 This paper explained the composition of 

 petroleum from different sources, and de- 

 scribed the series of hydrocarbons that 

 make up the great body of petroleum. In 

 Pennsylvania oil the series C^H^^^^ pre- 

 dominates in the lower distillates and con- 

 tinues to include solid paraffine hydro- 

 carbons. Pennsylvania oil also contains 

 the series C^H^^^ and the series C^H^^^'.j, 

 and probably also series still poorer in 

 hydrogen in the less volatile portions. 



Ohio oil has much the same composition, 

 with the addition of the series C^H^^^ _ ^, and 

 probably other series still poorer in hy- 

 drogen. 



