May 9, 1913] 



SCIENCE 



725 



able and ancient fossil fauna discovered by him 

 in the mountains of British Columbia, 2,000 feet 

 above Field, on the Canadian Pacific Railway. 



The fossils are most beautifully preserved and 

 include such delicate forms as medusae (jelly 

 fishes), holothurians (sea cucumbers), finely pre- 

 served marine shells of various kinds and a large 

 variety of crustaceans. Some of the latter are so 

 perfectly preserved that the branchia, legs and 

 alimentary canal are shown, and even in several 

 forms the liver is so perfect that the ramifications 

 of the tubes through it are reproduced by photog- 

 raphy and thus illustrated by lantern slides. 



Altogether over 80 genera of invertebrate fossils 

 have been found from a bed not over 5 feet in 

 thickness. They are all of marine origin and lived 

 at a period when there were no vertebrates (fishes, 

 reptiles, mammals) in existence. 



The Alleghenian Divide and its Influence upon 



Fresh-water Faunas: Arnold E. Ortmann, 



Ph.D., ScD. 



Although it is well known that the Allegheny 

 Mountains form a general boundary between the 

 aquatic forms inhabiting their western and eastern 

 slopes, particulars about the relations of the two 

 faunas were missing. In fact, the fundamental 

 facts, the actual faunas of the various streams, 

 chiefly in the mountains, were unknown. 



The writer furnishes first these facts for a 

 number of aquatic forms of life, chiefly the fresh- 

 water mussels, the Pleurocerids and the crayfishes, 

 covering the region from the New York-Pennsyl- 

 vania state line to the northern boundary of Ten- 

 nessee. The main results are, that the groups 

 mentioned have not been transported over land to 

 any extent, and consequently are apt to furnish 

 evidence as to the former drainage conditions. 

 The Allegheny Mountains have acted most of the 

 time as an effective barrier to the dispersal of 

 fresh-water life, surely so since the end of the 

 Cretaceous. The Atlantic side received its fauna 

 from the Interior Basin, but not across the moun- 

 tains, but around their northern and southern ends. 

 A few instances are known, where single species 

 have crossed the divide, and these cases are found 

 in two sharply-reetricted regions: they are prob- 

 ably due to stream piracy. 



Neutralization and Elimination of Toxic Sub- 

 stances: Oswald Schkeineb, Ph.D. 



Progressive Evolution among Hybrids of (Enothera 

 (illustrated) : Bradley M. Davis, A.M., Ph.D. 

 Introduced by Professor John M. Macfarlane. 

 Certain cultures of hybrids between (Enothera 



biennis and (Enothera grandiflora have presented 

 in the second generation a high degree of progres- 

 sive advance in flower size and in the size of the 

 leaves and the extent of their crinkling. A hy- 

 pothesis for such progressive evolution is offered 

 by the Mendelian principle of recombination of 

 factors for large size on the assumption of mul- 

 tiple factors for the dimensions of organs, but 

 this hjrpothesis also demands the presence in the 

 same culture of groups of plants containing the 

 factors for small size. When in an F, generation 

 there is a considerable group of plants with 

 flowers larger than those of the larger parent 

 there should also be expected corresponding groups 

 with flowers as small or smaller than those of the 

 smaller parent. This follows on the Mendelian law 

 of the conservation of factors by which the factors 

 contained in an Fj hybrid must all come out in an 

 F, generation, provided that this generation is 

 sufficiently numerous and that the formation and 

 mating of gametes present no exceptional fea- 

 tures. In Fj generations of about 1,000 and 1,500 

 plants, respectively, there were no groups of plants 

 with flowers as small as or smaller than those of 

 biennis, the small-flowered parent. There were 

 thus no groups to balance the large proportion of 

 plants with flowers larger than those of the 

 grandiflora parent. The cultures as a whole pre- 

 sented a marked advance in flower size. 



A similar situation was presented by the char- 

 acter of the foliage in certain F^ generations. The 

 leaves throughout the mass of these cultures were 

 much larger than those of the parents and gen- 

 erally much more crinkled. There was thus a 

 marked progressive advance in leaf size with the 

 absence of small-leaved groups of plants, and it is 

 difficult to explain the results on strict Mendelian 

 principles of segregation according to which 

 groups in an P, generation containing the factors 

 for large leaf-size should be accompanied by cor- 

 responding groups containing the factors for small 

 leaf-size. 



There was in these F^ generations abundant 

 evidence of segregation as shown in a range of 

 variation far above that presented by Pi genera- 

 tions, but this range was between groups of plants 

 with flower and leaf size much greater than those 

 of the two parents. Thus the petals in the larger- 

 flowered groups were 1 cm. longer than those of 

 the grandiflora parent with petals 3.3 cm. long, 

 and the flowers of the smaller groups were two or 

 more times larger than those of the biennis parent 

 with petals 1.3 em. long. 

 , Certain of the Fj generations presented classes 



