Metamorphosis is a most dramatic example of hormonally regulated genetic reprogramming during postembryonic development. The initiation and sustenance of the process are under the control of ecdysteroids in invertebrates and thyroid hormone, 3,3', 5-triiodothyronine, in oviparous vertebrates. Their actions are inhibited or potentiated by other endogenous or exogenous hormones - juvenile hormone...

Three tumors of widely differing structure occurring in, Salientia (Amphibia) are described. They are: (a) a nephroblastoma, (b) an atypical facial papilloma or melano carcinoma, and (c) an epithelioma resembling ulcus rodens. The first two tumors oc curred in specimens of the South African claw-footed toad (Xenopus laevis D.), the third in a specimen of the common grass frog (Rana temporaria L.).

This article gives a short and personal portrait of Ernst Hadorn (1902-1976), one of the most influential developmental biologists in Europe. Hadorn initially worked with amphibia, but then soon turned to Drosophila where he very successfully studied lethal factors and the development of imaginal disks.

In this review of alternative tests to whole-animal rodent studies, the use of sub-mammalian and sub-vertebrate systems is investigated. The history, methodology, known limitations, end points, dose response, and requirements of virus, hydra, planarian, cricket, fish, amphibia, Drosophila, and chicken embryo systems are discussed.

The life cycle of the sea lamprey, Petromyzon marinus, includes two metamorphoses. At the end of a period spent as a blind larva, buried in the mud of streams, a first metamorphosis prepares it to migrate downstream to the sea or a lake for its growth phase. Then, following a second metamorphosis, it migrates upstream as a sexually mature adult to spawn and die. The downstream migrants have a v...

Podosphaera (Sphaerotheca) euphorbiae on Euphorbia epithymoides (= E. polychroma, cushion spurge) is reported for the first time in North America. Neoerysiphe (Erysiphe) galeopsidis on Lamium amplexicaule (henbit), Blumeria (Erysiphe) graminis on Festuca idahoenis (Idaho fescue), Taphrina johansonii on Populus tremuloides (trembling aspen), and Taphrina occidentalis on Alnus rubra (red alder) a...

Question: Do caecilians follow Bergmann’s rule? Hypothesis: Bergmann’s rule explains the wide variation in body sizes found among populations of the terrestrial caecilian Schistometopum thomense. Field site: This is a range-wide study incorporating most terrestrial habitats throughout the island of São Tomé in the Gulf of Guinea. Methods: We performed morphological measurements on 95 museum spe...