EMBRYOLOGICAL, REPRODUCTION, ETC. Gen. Sub. 73 
Wagner (722), Herbst (295). — Theory of development : The real causes 
of development are all internal, in the constitution of the fertilised ovum, 
which is an Ursachen-dep6t ; the environment is only a condition of 
development, not a cause ; Wagner (723). — Bonnet’s theory of evolu- 
tion ; Whitman (753). — Theories of development, criticisms and 
suggestions ; Haacke (272). — Theory of development : argument that 
Weismann’s theory of determinants leads to the old preformationist 
“ emboltement,” and this to creationist dogma. So Hertwig reflects on 
the anlage the high organisation of its result; Haacke (272). — Epigenesis 
and evolution ; Haacke (272). — The anlage : not necessary or justifiable 
to postulate a highly organised anlage for a highly organised result. 
Specification of cells is a function of their position and relations; Haacke 
(269, 272). — Against the mosaic theory ; Garbowski (232). — Classifica- 
tion of external and internal formative stimuli ; Herbst (295). 
Phylogenesis of the amnion : possibility that the Protamniota were 
viviparous Amphibians, in which a pseudo-meroblastic blastodermic 
vesicle arose by a collection of fluid between the cells of the hypoblast. 
Suggestion that the amnion began to be formed from the covering layer 
of the Amphibian epiblast. Amnion and trophoblast are closely 
associated in their phylogenesis, and are to be regarded as products 
formed by separation from the outer epiblast layer ; Hubrecht (316). 
8. Reproduction, Sex, and Heredity. 
a. j Reproduction and Sex . 
Some problems in the physiology of reproduction ; Klees (345). — 
Reproductive organs, development of. Summary of recent work ; Born 
(55).— Very simple mode of reproduction, like fragmentation or rupture, 
in the Foraminifer Calcitubapolymorpha ; Schaudinn (625). — Plastogamy 
in Foraminifera ; Schaudinn (628). 
Meaning of conjugation phenomena in Infusoria ; Beard (26, 28). 
Theory that alternation of generations, with aposporous formation of 
the sexual generation, is of general occurrence in Metazoa ; Beard 
(26, 27). — Criticism of Beard’s theory ; MacMillan (418).— Law of 
budding in Medusae ; CilUN (107). — -Budding in Syllis ra mosa, intercalary 
and regenerative ; Oka (499). — Non-simultaneous production of the two 
sexes in colonies of exotic social bees ; P^rez (520). — Mystery of birth ; 
Grant Allen (4). 
Determination of sex : Conditions inducing appearance of males in 
DapTinids : tendency of unfavourable conditions to induce unsexuality ; 
Keriierv^ (339) — Determination of sex ; Stratz (674), Gessner : in 
bee ; Sharp (285), p. 499. — Queen-bee incapable of producing drone- 
eggs, i.e ., on the usual theory, unfertilised eggs. The defect may have 
been in the innervation of the muscular ring closing the duct of the 
receptaculum seminis, or in the musculature itself, or in the size of the 
tube, or in over abundant glandular secretion ; Grobben (262). 
