ect's body. In
several closely allied genera, as in _Dielytra_, there are two perfect
nectaries; the pistil is straight, and the hood slips off on either
side, according as the bee sucks either nectary." In the flowers of
_Corydalis_, which were provided with two perfect nectaries containing
nectar, Mr. Darwin considers that there has been a redevelopment of a
partially aborted organ, accompanied by a change in the direction of the
pistil, which becomes straight, while the hood formed by the petals
slips off in either direction, "so that these flowers have acquired the
perfect structure, so well adapted for insect agency, of _Dielytra_ and
its allies."

[Illustration: FIG. 124.--Two-spurred flowers of _Corydalis_.]

[Illustration: FIG. 125.--Section through two-spurred flowers of
_Corydalis_, Magnified.]

Peloria, then, is especially interesting physiologically as well as
morphologically; it is also of value in a systematic point of view, as
showing how closely the deviations from the ordinary form of one plant
represent the ordinary condition of another; thus, the peloric
Calceolarias resemble the flowers of _Fabiana_, and De Candolle,[242]
comparing the peloric flowers of _Scrophulariaceae_ with those of
_Solanaceae_, concluded that the former natural order was only an
habitual alteration from the type of the latter. Peloric flowers of
_Papilionaceae_ in this way are indistinguishable from those of
_Rosaceae_. In like manner we may trace an analogy between the normal
one-spurred _Delphinium_ and the five-spurred columbine (_Aquilegia_),
an analogy strengthened by such a case as that of the five-spurred
flower of _Delphinium elatum_ described by Godron.[243] The _Corydalis_,
before referred to, is another illustration of the same fact, the
structure being the same as in _Dielytra_, &c.

The ordinary irregular flowers may possibly be degenerated descendants
of a more completely organized ancestor, and some of the cases of
peloria may therefore be instances of reversion; some ancient _Linaria_
may, perhaps, have had all its petals spur-shaped, and the cases of
irregular peloria now found may be reversions to that original form.
When both regular and irregular forms of peloria occur on the same
plant, as they frequently do in _Linaria_, the one may be perhaps
considered as a reversion to a very early condition, the other to a
later state, when all the petals were irregularly formed. But before we
can assert the truth