Parapodium Sentence Examples
Typically, the parapodium consists of two processes of the body on each side, each of which bears a bundle of setae; these two divisions of the "limb" are termed.
The notopodium may be rudimentary or absent and the entire parapodium reduced to the merest ridge or even completely unrepresented.
Naturally, it is among the free living forms that the parapodium is best developed, and least developed among the tubicolous belongs typically a long tentacle, the cirrus, which 'r podium or neuropodium, and may be developed into an arborescent gill or into a flat scale-like process, A the elytron (in Polynoe, &c.).
The dorsal surface of the kidney extends to the left beyond the shell-chamber beneath the skin in the space between the shell-chamber and the left parapodium.
It is probable also, as already mentioned, that the leaf-like appendages of the Phyllopoda are of a primitive type, and attempts have been made to refer their structure to that of the Annelid parapodium.
The reduction of the outgrowth-bearing " corm " of the parapodium of either a Chaetopod or an Arthropod to a simple cylindrical stump, devoid of outgrowths, is brought about when mechanical conditions favour such a shape.
A common modification of the chief ramus of the Arthropod parapodium is the chela or nipper formed by the elongation of the penultimate joint of the ramus, so that the last joint works on it FIG.
The parapodium is represented with its neural or ventral surface uppermost.
It seems probable that there are branchial plumes or filaments in some Arthropoda (some Crustacea) which can be identified with the distinct branchial organs of Chaetopoda, which lie dorsal of the parapodia and are not part of the parapodium.
On the other hand, we cannot refuse to admit that any of the processes of an Arthropod parapodium may become modified as branchial organs, and that, as a rule, branchial out-growths are easily developed, de novo, in all the higher groups of animals.
AdvertisementThe most extreme disguise assumed by the Arthropod parapodium or appendage is that of becoming a mere stalk supporting an eye - a fact which did not obtain general credence until the experiments of Herbst in 1895, who found, on cutting off the eye-stalk of Palaemon, that a jointed antenna-like appendage was regenerated in its place.