In other cases, however, the medusa-individuals become sexually mature while still attached to the parent polyp, and are then not set free at all, but become appanages of the hydroid colony and undergo degenerative changes leading to reduction and even to complete obliteration of their original medusan structure.
As has been shown above, the closing up of the sub-umbral cavity is one of the earliest degenerative changes in the evolution of the gonophore, and we may regard it as the umbrellar fold taking on a protective function, either temporarily for the bud or permanently for the gonophore.
Degenerative simplicity is never uniformly distributed over all the structures of the organism.
The feathers of a peacock afford a convenient example of primitive and degenerative simplicity.
The one-sided specialization and the peculiar metallic colouring of the lateral tail feathers mark them as the extreme terms of a degenerative series, whilst the symmetry, likeness of constituent parts inter se, and absence of specialized pigment, as well as the fact that they differ little from any average feather of birds in general, mark the contour feather as primitively simple, and as the starting-point from which the highly elaborated eye-painted tail feather has gradually evolved.
The central part of the obstructed area very soon undergoes degenerative changes, and rapidly becomes decolourized.
- In many pathological conditions we have degenerative products of various kinds formed in the tissues.
The study of autolytic phenomena which closely simulates the changes seen in the degenerating cell has thrown much light on these degenerative processes.
Certain degenerative changes in the supra-renal glands may lead to Addison's disease, which is characterized by an excessive pigmentary condition of the skin and mucous membranes.
Certain peculiar substances, probably degenerative products, some of them reducing copper, are occasionally met with.
The chief work has been the detection of chronic changes in the cortex of the brain, by staining and other histological methods, in degenerative affections of this organ - Theodor Meynert (1833-1892), W.
New elements appear in addition to degenerative changes in the normal red corpuscles.
In all Malacocotylea except the Holostomidae the ensuing change is a degenerative one.
TARDIGRADA, apparently Arthropodous animals whose relationship to the great classes of this sub-kingdom is masked by degenerative modification.