Acidovorax-like symbionts in the nephridia
The attached figures clearly showed two pairs of nephridia, the gizzard in segment 6, and holandry as the generic characters for Brachydrilus, although a pair of spermathecae in 12/13 was evaluated as being in an 'abnormal position'.
Trotzdem lasst sich die systematische Stellung der Art genau feststellen, und auch die noch erkennbaren artlichen Charaktere sind zur Wiedererkennung der Art vollkommen ausreichend.' [And also the nephridia are present only as rudiments.
Both authors indicated a proandric condition (later not confirmed) and did not observe nephridia. Michaelsen (1913: 437) accepted Beddard's priority for zuluensis, making his zulu synonymous therewith.
Michaelsen (1918: 332), in synonymizing the genus Brachydrilus under Tritogenia, accepted duplication of nephridia as the exclusive generic character for this genus, and wrote '...
Thus, digestive gland tubules, intestine, nephridia, gills, gonad, and connective tissue of the mantle were the main sites invaded.
During an initial stage, gills, nephridia, connective tissue of mantle, gonad, and digestive system were infiltrated by hemocytes, and a few neoplastic cells were apparent (Fig.
These sacs (thread glands in Wilson, 1932) are destined to become the first nephridia in the adult worm, derived from the ventral epidermis of the larva.
By the time the rudiment fully encircles the hindgut, not only are the nephridia, chaetae, and uncini present, but also the segmental body wall musculature, chaetal musculature, and future coelomic lining have formed (Fig.
At the same time, the trunk begins to straighten out: as the sock unrolls, the digestive tract is pulled down and enclosed, with the anterior nephridia and juvenile musculature adopting their appropriate positions (Fig.
Internally, the thoracic segment typically inherits the first two pairs of nephridia, matching the two pairs of juvenile chaetae.
The early development of the nephridia
in amphioxus: introduction and part I, Hatschek's nephridium.