THE REG 10 X OF THE STIXAL CORD 



399 



disappeared, the nephric organs would still remain, not as coxal 

 glands, but as purely somatic excretory glands. They would still be 

 homologous with the annelid segmental organs, or with the coxal 

 glands, but would arise in toto from a part of the ventral ccelom or 

 nephroccele, more dorsal than the former appendicular part, because 

 the appendages and their enclosed ccelom are always situated ventrally 

 to the body. Again, according to Sedgwick, the nephric tubules are 



App 



Fig. 157. — Transvkrse Section of Peripatus Embryo. (After von Kennel.) 



Al., alimentary canal; N., nerve-cord; App., appendage; I, II, III, the three 

 divisions (lateral, median, and dorso-median) of the ccelom. 



e.v 

 i v 



App 



Fig. 158. — Section op Peripatus. (After Sedgwick.) 



Al., alimentary canal; N., nerve-cord; App., appendage; i.v., internal, and e.v., 

 external vesicles of the segmented excretory tubule (coxal gland). 



connected with two ccelomic vesicles, the one in the appendage the 

 internal vesicle, and the other, the so-called bladder, or the external 

 vesicle, in the body itself, close against the nerve-cord. Sedgwick 

 appears to consider that either of these vesicles may form the end- 

 sac of a nephric tubule, for he discusses the question whether the 

 single vesicle, which in each case gives origin to the nephridia of the 

 first three legs, corresponds to the internal or external vesicle. He 



