BOOK-NOTES, NEWS, ETC. 167 



to biological science. " The dominant and recessive factors in the 

 phenomena of Heredity have to be reckoned with in the improve- 

 ment or degeneration of the race. The one set of factors, like the 

 other, are under the directive influence of natural selection ; and 

 that higher agency which is causal rather than directive must be 

 left to control and fix those factors which make for the good of the 

 race, and to eliminate those factors which retard its progress. 



Finally — and this seems to be the gist of Mr. Lock's arguments 

 the author's work is intended to show that Mendel's Law of 

 Heredity is considerably simpler than, and completely replaces (in 

 the opinion of the most competent biologists), Weismann's Theory of 

 Inheritance, the fashionable biological creed of some years ago : 

 though it must not be forgotten that many of the conceptions used 

 in the Mendelian expression of the facts are unconsciously borrowed 

 from Weismann's theory. As Dr. J. T. Cunningham points out, 

 in discussing Eimer's Organic Evolution, selection, whether natural 

 or artificial, is analogous to the process of denudation in geology. 

 It explains extinction of forms, gaps, and intervals which separate 

 groups of genera, just as denudation explains the want of con- 

 tinuity in the stratified rocks. 



Frederic N. Williams. 



BOOK- NOTES, NEWS, Ac. 



At the meeting of the Linnean Society on 7th March, 1907, 

 Messrs. H. & J. Groves exhibited a series of specimens of Nitella 

 omithopoda A. Braun, collected by the Rev. Canon Bullock Webster. 

 This rare species has only been found in a small district in the 

 West of France, from Angouleme in the north to the south of 

 Arcachon, and doubtfully in one locality in Portugal. The especial 

 interest of the specimens exhibited, which were collected to the 

 south of Arcachon in March and April, 1906, was that they repre- 

 sented gatherings of the plant from very different habitats and 

 showed great variations. The plants collected in shallow ditches 

 were already in full fruit, while those from running water and from 

 Lake Cazan were quite immature, and so far sterile. Only a few 

 specimens of this species have previously reached England, and the 

 collection exhibited was probably by far the most extensive series 

 of forms yet obtained. Braun recognized two forms— the more 

 tvpical one almost resembling in habit some forms of our N. tenuis- 

 sima (this form was called f. moniliformis by Prof. Migula), and the 

 other var. laxa, which resembles N. gracilis. Among the specimens 

 were some from roadside ditches near Arcachon, representing a 

 third and very distinct form ; this may be called var. robust a. It 

 is 4-5 in. high, very dark green, much more robust than the 

 ordinary form, and with comparatively short ultimate rays to the 

 branchlets, giving it the appearance of N. mueronata in miniature. 

 N. omithopoda is interesting as representing in Europe Braun's 

 section Polijarthrodactyla. The headquarters of the species in this 



