DIRECT DEVELOPMENT. 211 
with design”—we have only to remember the fate of 
the tapeworm’s eggs—that by the larval state the 
period of infancy and weakness is prolonged, and the 
period of maturity and efficient care for the continuance 
of the species delayed, it follows that curtailments and 
reductions, consequent on adaptation have, as advan- 
tageous modifications, a prospect of perpetuation. As 
‘in Amphibians the prolongation of the larval phase may 
be effected by natural circumstances and artificial ex- 
periments, so in like manner a compression of the phases 
of transformation, and a general curtailment of the 
metamorphosis is imaginable. In the class of Amphi- 
bians we have, in fact, several examples of curtailed and 
modified metamorphosis which bridge over the apparent 
chasm between development with and without transfor- 
mation, and render direct development comprehensible 
as being gradually acquired. Amphibians will endea- 
vour to extend themselves wherever they are invited by a 
sufficient supply of insects, and the black salamander of 
the mountains (Salamandra atra) has even overcome the 
impediment which might have been deemed insurmount- 
able, the absence of water for its larva. It does not lay 
its eggs like its congeners, but only two are received 
into the oviduct, and the fluids secreted from its walls 
replace the marsh to them and to the larve which 
emerge from them. Here, and not when separated from 
the parent, do the gills make their appearance, while the 
other eggs, gradually following, are devoured by the 
hungry larve. The metamorphosis of the black sala- 
mander, respecting which, unluckily, no recent investi- 
gations have been made, thus takes place within the 
parental body, and there is no difficulty in imagining 
