In Acanthobdella the testes are, however, not contained in the general coelom, and the nephridia lie in the septa.
In this worm the paired nephridia exist in most of the segments of the body, and their form (see fig.
Commonly the nephridia are strictly paired a single pair to each segment, while the branches of the blood vascular system are similarly metameric.
The Oligochaeta are the only Chaetopods in which undoubted nephridiamay possess a relationship with the alimentary canal.
Nephridia in two series; large, anterior nephridia followed by small, short tubes in abdomen.
Rhynchelmis, which afterwards become by an enlargement and opening up of the funnel the permanent nephridia of the adult worm.
In the genital segments of Eudrilus the nephridia are present, but the funnels have not been found though they are obvious in other segments.
In any case the nephridia which occupy the segments of the body generally are first of all represented by paired structures, the "pronephridia," in which the funnel is composed of but one cell, which is flagellate.
Sperm ducts and atria as in Limicolae; egg sacs large; body wall thick; vascular system and nephridia as in Terricolae.
In Pontobdella and Branchellion the nephridia form a network extending from segment to segment, but there is only one pair of funnels in each segment.
Nephridia generally paired, often very numerous in each segment, in the form of long, much-coiled tubes with intracellular lumen.
Nephridia as a rule with abundant vascular supply.
In both, the nephridia are all alike; there are no jaws; the prostomium rarely has processes.
Argiope) there is one such pouch on each side, just below the base of the arms, and into these the nephridia open.
The kidneys or nephridia open internally by wide funnel-shaped nephridiostomes and externally by small pores on each side of the mouth near the base of the arms.
The dorsal branch sends a blind twig into each of the diverticula of the dorsal mantle-sinus, the ventral branch supplies the nephridia and neighbouring parts before reaching the ventral lobe of the mantle.
The nephridiaare not easily distinguished, though they are very numerous.
The nephridia show as loosely scattered fragments in the body cavity, at the right and left of the alimentary canal.
Cunningham,[412] of an internal segmental duct in Lanice, into which several nephridia opened, seemed to strengthen this view.
Borrowing, as we may, the nephridia from the Nemertines, and the lateral in addition to the dorsal nerve, we find that Balanoglossus gives the most hopeful hypothetical solution of the pedigree of Vertebrates.
The Annelid theory was firmly supported by Eisig, who in his elaborate monograph on the Capitellidæ[410] maintained against Fürbringer the genetic identity of the Annelidan nephridia with the kidney tubules of Vertebrates.
In a number which are associated into a sub-family Eudrilacea there are two paired calciferous glands and a single unpaired one, while the paired nephridia open by a large pore on to the exterior.
The nephridia moreover do not open on to the exterior by single pores, but form a network within the thickness of the body wall and then open by numerous pores.
The paired nephridia have disappeared and their place is taken by several, often quite numerous, pairs of much smaller nephridia called on that account 'micronephridia' instead of 'meganephridia.
The genus agrees with many aquatic forms in the fact that the nephridia are not present in the earlier segments of the body, not indeed putting in an appearance until about the thirteenth segment or even later.
They consist as a rule of but few segments to most of which a pair of nephridia belong.
The pores of thenephridia lie in front of the dorsal pair of setae or in a line corresponding to the position of those setae where the arrangement has become irregular.
The nephridia are paired structures and commence early.
The nephridia are either paired or numerous and these various characters allow of the sub-family being split up into sixteen genera or thereabouts.
Thus the nephridia are without a plexus of blood capillaries surrounding them, a state of affairs which also occurs in some of the slender Ocnerodrilinae among the earthworms.
It retains the characteristic alternation in the position of the nephridia of Maoridrilus, and other structural similarities unite the two genera.
Dissection to show alimentary canal in section andnephridia of earthworm.
The function of the nephridia is to carry off waste matter from the fluid which fills the body-cavity.
The wide funnels of the nephridia of this region are possibly of coelomic origin.
Previously to Hoek's discovery a brown-coloured investment of the auricles of the heart of the oyster had been supposed to represent the nephridia in a rudimentary state.
Diagrams showing the Relations of Pericardium and Nephridia in a Lamellibranch such as Anodonta.
As in Cephalopoda (and possibly other Mollusca) water can be introduced through thenephridia into this space.
Hence it passes through the vessels of the glandular walls of the nephridia right and left into the gill-lamellae, whence it returns through many openings into the widely-stretched auricles.
All cavities that are found in these lower animals besides the digestive gut-cavity are direct processes from it (with the exception of the nephridia in the platodes).
The three pairs of nephridia in the three foremost pairs of legs are very rudimentary, consisting, so far as I have been able to make out, solely of the collecting vesicle and the duct leading from them to the exterior.
These organs are probably of an excretory nature, and I consider them homologous with the nephridia or segmental organs of the Chaetopoda.
In this genus it develops no perivisceral portion, as in other groups, but gives rise solely to the nephridia and to the reproductive organs.
The nephridiavary in number from a single one in Bonellia to three pairs in many species of Thalassema.
Such cannulated cells are characteristic of the nephridia of many worms, and the organs thus formed in the embryo Limnaeus are embryonic nephridia.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "nephridia" in a variety of sentences. We hope that you will now be able to make sentences using this word.
