52 Gen. Sub. i. general stiBjficTSk 
Roots grow only in contact, polyps only when freely washed (stereomof* 
phism). The importance of the osmotic factor in growth ; Loeb 
(316). 
“ Anlagen ; ” Mitchell (359). 
Arguments from development of fishes against Weismann and for 
epigenesis ; Loeb (311). 
Relations of ontogeny and phylogeny ; Gegenbaur (183). 
Teleological aetiology : Inadequacy of aetiological theories which postu- 
late new origins, functionless rudiments, and the like, which seek to 
explain the cause of an origin in terms of its final function. On the 
contrary, the material fora new organ is to be found in some pre-existing 
organ. Illustration of this by theory of origin of paired fins from 
branchial arches ; Gegenbaur (184). 
Theory of development ; Hertwig (235). 
Analysis of stimuli effective in development ; Herbst (231, 232). 
Present state of embryology as regards germinal layers ; Hatsciiek 
(222). Of Lwoff (318). 
Relation of germinal layers in buds of hydroids ; Lang (292). 
Origin of sympathetic system : From spinal ganglia, and therefore 
from ectoderm ; Mazzarelli (340). 
Mid- brain and accessory vesicles ; Locy (309). 
Embryology of the eye ; Holden-Ward (249). 
Thyroid : Paired origin of median thyroid gland of pig ; Jacoby (259) 
Ectodermic origin of scleroblasts ; Klaatscii (273). 
Metameric segmentation in the medullary folds and embryonic rim • 
Locy (309). 
Development of the pancreas ; Laguesse (290) . 
Critical summary as to development of venous system in Vertebrates ; 
Hochstetter (245). 
Critical summary of recent work on the development of the head ; 
Frorief (174) : metamerism of head; Hoffmann (248): development of 
the head ; Kupffer (288). 
Nature and origin of blood-cells ; Disse (121). 
Post-embryonic development of Mammalian skeleton ; Solger (514). 
Origin of Vertebrate skeleton : Summary of recent work by Gorono- 
witsch, Kastsclienko, Platt, Klaatsch ; Kingley (271). 
Mechanical processes in development ; His (243). 
Experimental Embryology. 
Experimental embryology ; Marshall (332), Herbst (231, 232), 
Loeb (312). — General account of recent researches ; Thomson (534), 
Wilson (579a). 
Methods of study of the mechanics of development ; Roux (464), cf. 
Burger (75). 
