THEORY OF EVOLUTION, Gen. Sul). 13 
Roux, W. Zur Meehauik der Eutwickelung. Z. Biol, xxi, pp. 1-118. 
Mechanics of development. Self-differentiation , where the specific 
nature of the modification is determined by the energies of the system, to 
be distinguished from correlative differentiation , or change determined by 
action and reaction between the system and its environment. 
Yirchow, R. [See Heredity.] 
Every variation means some disturbance of the organismal diathesis, 
and is so far pathological. Certain varieties, species, and oven genera, 
may certainly be described as pathological. Discussion of teratology 
in relation to variation and heredity. 
3. Environment. 
Barfurth. D. Biologie der Forellen. Arch, inikr. Anat. xxvii, 
pp. 121-178, 2 pis. ; J. R. Micr. Soc. vi, p. 768. 
Sterility of trout temporary, caused especially by prevention of 
spawning by reason of want of suitable depositing ground, unfavourable 
temperature, nutrition, &c ; degeneration aud reabsorption of the hyper- 
trophied organs ; finally, permanent sterility, or the production of 
weak forms. 
■ . Experimentelle Untersuchen fiber die Yerwandlung der Frosch- 
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. Ueber Yorsucho zur Yerwandlung dor Kaulquappon. Tag. Dout. 
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pp. 490 & 491. 
Brandt, R. Die Sphaarozoen. Naples Monograph, xiii. 
Sensitiveness to changes in salinity, indifference to light, &c. - 
Brauer, Fr. Ueber Artemia und Branchipus. Zool. Auz. iv, 
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Criticism of conclusions of Schmankewitsch. 
Claus, C. Untersuchungen fiber die Organisation und Entwic-klung von 
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Inter alia , critique as to conclusions of Schmankewitsch on effects of 
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Dall, W. H. Report on Mollusca. Bull. Mus. C. Z. xii, pp. 171-318, 
9 pis. 
Inter alia , general notes on influence of environment. 
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C.R. ciii, No. 16, pp. 696 & 697. 
DOsing, C. Ueber die Farbung und Zeichnung der Thiere. Kosmos, 
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Review of Eimer, Weismann. 
— — . [See Rcprod.] 
