454 Beard and Murray. — Reproduction in Animals 
abortive spores, and the formation of one true spore alone 
appears to be out of the question ; for, in order that cells 
with the reduced number of chromosomes, i. e. spores, should 
arise, four of them at least must be formed. (2) That there 
is no spore-formation is, of course, also proved by the cir- 
cumstance that there is no reduction before the origin of the 
gametozooid, and as previously shown, the primary object of 
spore-formation is to effect a reduction. 
The modifications in development which this aposporous 
alternation brings about are far too numerous and too varied 
to admit of treatment here. It would be necessary, even 
with the facts already available, to write a treatise on animal 
development from this standpoint, in order to display them. 
But it may be of interest to indicate one or two develop- 
mental facts, which clearly have their natural interpretation 
in an aposporous formation of the sexual generation in the 
Metazoa. 
The marine Annelida with an obvious larval development 
admit readily of inclusion in such a scheme as that suggested. 
Kleinenberg 1 , in his brilliant Lopadorhynchus memoir, has 
amply demonstrated such an alternation as that here recog- 
nised, while just failing to draw the manifest conclusion. 
By way of parenthesis it may be remarked how marvellously 
close on a recognition of this ‘ law of development ’ Kleinen- 
berg’s meditations, along with those of Johannes Muller and 
Von Baer, really verge. 
A Chaetopod origin of the group of Hirndinea is commonly 
admitted, and in them R. S. Bergh has demonstrated facts in 
his memoirs furnishing as valuable confirmation of the views 
here advocated as could be wished. 
Passing next to the group of the Oligochaeta , we are 
apparently brought to a standstill in our further search for 
confirmation. But not really so. When we take up the 
researches of E. B. Wilson 2 , these at first sight seem hope- 
1 Zeitschrift f. Wiss. Zool., Bd. XLIV, 1886. 
2 Wilson, E. B., The Germ-bands of Lumbricus. Journ. of Morphology, 
Vol. i, 1887. 
