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KARM NARAYAN BAHL 



In such preparations of embryos (Text-fig. 5, part of an 

 embryo about 9 mm. long) we can follow these nephridial 

 rudiments antero-posteriorly. The dorsal vessel in embryos 

 of this age is double in the posterior portion, and consists of 

 two lateral vessels lying on the sides of the gut. Anteriorly, 



Text-fig. 4. 



Portion of an embryo mounted flat after removal of the gut, 

 showing the relative position of the developing integumentary 

 nephridia in successive segments. b.w„ body-wall ; i.s., interseg- 

 mental septa ; n.c, nerve-cord. 



however, the two dorsal vessels converge and fuse to form 

 one single vessel, and we find it as such in the mid-dorsal hne 

 in the anterior part of the embryo. Following the nephridial 

 masses from the septum 15/16, we can trace them backwards 

 a good way beyond the point where the two converging vessels 

 meet to form the single dorsal vessel (Text-fig. 5). The further 

 development of these septal nephridia can be followed in 

 whole mounts of embryos, 9 to 18 mm. in length, flattened 



