322 DARWINISM TO-DAY. 



keenly composed. I believe that Eimer's work and theories should 

 have more attention from students of evolution then they now get. 



14 Dean, Bashford. "Evolution in a Determinate Line, as Illus- 

 trated by the Egg-Cases of Chimaeroid Fishes," Biol Bull., Vol. 

 Apparent deter- VII, pp. 105-112, 1904. In this paper the author 

 minate evolution, expresses his belief that the conditions existing in the 

 curious inter-related adaptations between eggs and egg-cases of the 

 shark-like fish, Chimaera, can be explained only on the basis of 

 determinate or orthogenetic modifications, in which modifications 

 neither natural selection nor the Lamarckian factors of use and 

 disuse can have played any part. The capsule or egg-case, although 

 "only indirectly connected with the egg, i.e., as a secretion formed 

 by the parent after the mechanism of heredity has already been 

 established in the egg, nevertheless foresees with startling exact- 

 ness the size and shape of the young fish when many months hence 

 it comes to hatch out, and it provides a series of progressive multi- 

 plications adapted to the physical needs of the young. It is evident, 

 accordingly, that if natural selection be adduced to explain the 

 present phenomena it encounters difficulties more numerous and 

 complex than in usual instances. In the latter cases selection con- 1 

 cerns itself with variations which affect the progeny directly; but 

 in the present case variations must have occurred in the lines both 

 of the progeny and, indirectly, of its far less indifferent capsule- 

 forming capabilities with result that a succession of closely corre- 

 lated stages in variation must have coincided in both distinct con- 

 ceptions." 



16 Plate, L., "Uber die Bedeutung," etc., p. 190 ff. 



16 Rosa, Daniel, "La Riduziorie Progressiva della Variabilita i 

 suoi Rapporti coll' Estinzione e coll' Origine della Specie," 1899. 

 Author believes that in animal life there is a gradual progressive 

 reduction of variation (or modification) necessitated by the well- 

 known fact that highly specialised forms have distinctly fewer lines 

 of modification, i. e. specialisation, left open to them than general- 

 ised forms; and that all groups of animals are of the nature of 

 series of more and more specialised forms. He bases this belief, as 

 far as facts go, on the well-known cases of the dying out of spe- 

 cialised species (Irish stag) and specialised groups (Cretaceous 

 reptiles), and on the alleged facts (which the author devotes many 

 pages to trying to show) that all present-day principal groups of 

 animals are related to each other solely by derivation from com- 

 mon very old and generalised ancestors. If there is less modifica- 

 tion possible, then there occurs actually less and less variability, and 

 the actually occurring variations will be only along certain lines, 

 i. e. there will be in this limited variability an actual basis for ortho- 



