On the structure of the branchiae of the gilled Oligochaete Alma nilotica
Ann and Mag Nat Hist 19(111): 348-360
Following a brief introductory reference to previous accounts of branchiate Oligochaeta, the author gives a detailed description of the branchiae, dealing especially with their external form, relation to body walls, histology and circulation. All layers of the body wall except the longitudinal muscles continue into the gills and the gill cavities communicate with the coelom. The afferent branchial vessels arise from the parietal branches of the ventral vessel and give rise to vascular loops in the gills which again unite to form the efferent branchials emptying into the commissural vessel. The very few gilled Oligochaeta known are distributed among 4 families and differ so much in position and structure that there is no possibility of common origin. Any resemblances are due to convergence.