The anatomy and histology of the blood system of the maldanid polychaetes Clymenella torquata and Euclymene oerstedi

The blood system of the flabelligerid polychaete, Flubelliderma commensulis has been explored by dissection, light and electron microscopy and absorption spectrophotometry. The main longitudinal vessels are the dorsal, ventral, perineural, sub-oesophageal, supra-oesophageal and heart. Each segment has a segmental vessel which communicates with the dorsal vessel i n thoracic setigers and the gut sinus in abdominal setigers. Branches of the segmental vessels in setigers 2-9 supply the gonads. A blood sinus envelopes most of the gut. Circulation is maintained by the pumping of the heart which immediately supplies blood to the supra-oesophageal ganglion, the branchiae and the palps. These are paralleled by a system of collecting vessels. The sinus of the supra-oesophageal ganglion receives a number of different axonal endings, some of which may be neurosecretory. The retroperitoneal vessels in their most developed form are composed of a n intima, longitudinal and circular muscles and a peritoneum. The heart vessel contains a cardiac body whose cells appear to contain vacuoles of blood pigment. The blood pigment exhibits the absorp tion characteristics of a chlorocruorin with maxima at 438, 558 and 606 nm.Previous studies on flabelligerid blood systems have been mainly partial anatomical accounts

The blood system of the flabelligerid polychaete Flabelliderma commensalis (Moore)

Spies

1973

The functional morphology and possible taxonomic significance of the parapodia of the maldanid polychaetes Clymenella torquata and Euclymene oerstedi

Pilgrim

1977

The morphology of the chaetae of the maldanid polychaetes Clymenella torquata (Leidy) and Euclymene oerstedi (Claparède) (= Caesicirrus neglectus Arwidsson, '11) are described and related to movements observed in the laboratory. Graphs are constructed of the number and length of the neuropodial chaetae of each chaetiger throughout the body of Clymenella and of species of the genera Euclymene, Macroclymene and Axiothella, and show a characteristic and relatively constant pattern for each species. This work suggests that in making taxonomic decisions, more attention should be paid to the overall pattern of the neuropodial chaetae and less to the confusing distinction between aciculae and rostral uncini.

The anatomy and histology of the nervous system and excretory system of the maldanid polychaetes Clymenella torquata and Euclymene oestedi

Pilgrim

1978

The nervous system of the maldanid polychaetes Clymenella torquata (Leidy) and Euclymene oerstedi (Claparede) (= Caesicirrus neglectus [Arwidsson, '11‐'12]) retains its primitive association with the epidermis. It shows only slight metamerism in the presence of larger collections of neurones opposite the parapodia and of larger nerves at the segmental boundaries. Multicellular giant fibers are present in the ventral nerve cord; giant neurones which show a characteristic pattern of distribution in each species are also present. The cerebral ganglia supply nerves to the prostomial wall, nuchal grooves and the wall of the buccal cavity, and a pair of large nerves from the circumpharyngeal connectives also appear to join the buccal system. The organs of special sense are the elongated prostomial nuchal grooves, and prostomial ocelli in Euclymene but not in Clymenella. Statocysts are absent. Four pairs of nephromixia are present. They lie in the aseptate anterior trunk, in chaetigers 5–9 of Clymenella, and 6–10 of Euclymene. The nephridiopores lie at the ventral ends of the neuropodia of chaetigers 6–9 and 7–10, respectively. Each nephromixium consists of coelomostome, tubule and contractile bladder. The wall of the tubule and bladder consists of both excretory and ciliated cells. Most of the cytoplasm of the latter forms a bounding layer at the outer surface. The cytoplasm of the excretory cells contains lipid material and appears to synthesize lipofuscin. The tips of the excretory cells swell, fill with granules, and break off in the form of vesicles which are periodically expelled in clouds from the nephridiopores. Glycogen is present, especially in the ciliated cells of the tubule and coelomostome. Granules of a lipoid nature accumulate in (or between) cells of the nephridia, epidermis, and some regions of the gut, and may be excretory. Lipid granules also appear to be synthesized by coelomocytes which eventually end up in masses in the ventrolateral coelomic cavities of the tail. The nephridia act as gonoducts, but show no seasonal variation in either size or histological structure.