TWO NEW SPECIES OF ONYCHOPHORA. 499 



witli legs in either the adult female of the species Weldoiii, 

 or the adult male of the species Horsti; though iu the 

 female of the latter species the duct was very highly de- 

 veloped (fig. 34). 



A typical renal organ is usually said to consist of four 

 parts: namely, the ccelomic end-sac; the thickened funnel; 

 the coiled tube; and the bladder. It appears, however, that 

 there is a fifth part which is, most probably, as constant as 

 any other part, without making an exception even of the 

 coelomic end-sac, which is always present. The part in ques- 

 tion is the ectodermal duct which puts the coelomic portion 

 of the organ in communication with the exterior. It varies 

 in length according to the position of the renal organ ; in 

 that of the ninth segment, which is represented in fig. 26, 

 this ectodermal duct is short; but in the one from the fourth 

 le('"-bearing segment which is shown in fig. 25 it is much 

 longer. Of the other parts, the bladder, the funnel, or 

 the coiled duct may be absent. In the renal organ of the 

 fourth and fifth leg-bearing segments the bladder is wanting, 

 while in those placed in the first, second, third, and the two 

 prsegenital segments, there is neither a differentiated funnel 

 nor a bladder, and the coiled tube is represented only by a 

 short, straight duct. 



A typical renal organ from the ninth leg-bearing segment, 

 with the five parts above mentioned, is shown in fig. 26. 

 The short duct situated externally to the bladder in the 

 above-mentioned figure is a well-marked structure, and its 

 distinctive histological cliaracters are clearly seen in fig. 31. 

 The lining cells of this ectodermal duct resemble exactly 

 those which cover the external body wall, wliile the lining 

 cells of the bladder approach much nearer to those of the 

 coiled tube. The bladder, it would appear, is notiiing moic 

 than a dilated portion of the outer end of the coiled tube 

 In the renal organ, shown in fig. 25, which has no dilated 

 bladder, the short duct represented in fig. 26 appears as a 

 much elongated tube which stretches from the level of the 

 nerve-cord to the renal papilla situated on the proximal side 



