1899] JJTORPHOLOGY OF THE STING IN HYMENOPTERA 245 
that the latter are not developed until the larval stage is reached, and 
are therefore in no wise comparable to the abdominal appendages 
which appear and disappear during the strictly embryonic period. In 
fact, he confirms the conclusion of Heymons that the leg-rudiments 
and the gonapophysal rudiments are in their nature quite distinct. 
Factors in the Growth of Muscle. 
WE have previously noticed Mr. Alexander Meek’s interesting conclu- 
sion that in the post-embryonic history of striped muscles in various 
mammals (cat, sheep, field vole, white rat) there is a reduction in the 
number of fibres accompanied by a considerable hypertrophy of the 
survivors. Dr. B. Morpurgo got a different result in examining the 
white rat, and Mr. Meek briefly answered him, maintaining his position 
that there really is in the history of a muscle “a struggle of parts 
within the organism,” and a resulting “survival of the fittest.” 
In a more recent paper (Journal of Anatomy and Physiology, 
Xxxili. 1899, pp. 596—608) he discusses the question in greater detail, 
and as the subject is one of much practical and theoretical interest, we 
quote his summing-up. “The life-history of muscle seems to be 
determined by (1) inherited qualities, present in the fertilised ovum, 
the evolution of which is controlled by (2) internal influences—internal 
secretion (including the effects of ‘sex’), the mutual influence of the 
muscles upon one another, and of the fibres upon one another, and 
the internal variations amongst the fibres; and by (5) external 
circumstances—work, food, habit, and indeed, the ordinary and 
extraordinary conditions of extra-uterine life.” 
“Up to the time of birth, in at any rate the higher mammals, 
perhaps in all the Eutheria, hyperplasia characterises the growth of 
muscle; while after or about birth, hyperplasia ceases, and extra- 
uterine life brings about a selection of some of the fibres at the expense 
of their neighbours. In other words, during extra-uterine life, muscle, 
according to its position, suffers more or less a reduction in the number 
of its fibres, the degree of which is expressive of its functional import- 
ance. The surviving elements are at the same time greatly hyper- 
trophied, and the extent to which this takes place is also expressive of 
the work which the muscle performs, or of which it is capable.” 
Water-Plants as Land- Winners. 
In The Naturalist for August Mr. Albert Henry Pawson makes a 
brief contribution to the study of the influence of water-plants on the 
