102 



ADAM SEDGWICK. 



of this part is poured into a branch given off from the main 

 duct at the bend (fig. 1, T). The posteriorly directed part 

 of the renal duct lies close to the dorsal edge of the part 

 running forward, and, like the latter, receives the efferent 

 ducts of bunches of glandular cseca (fig. 1). From the level 

 of the fifth shell-plate (fig. 1, O) to its posterior termination 

 (fig. 1, j9.o.), about to be described, it receives no gljandular 



Fig. 2. 



A diao^raramatic representation of a transverse section through Chiton 

 discrepmis at the level of the renal orifices {r.o.^ fig. 1). Dorsally is the 

 pericardial cavity wit-b the heart, separated by the pericardial floor from the 

 general body cavity (^.c), containing the viscera. Ventrally is the poste- 

 rior apparently median unpaired part of the kidney {k.t. and /t.c.) seen by 

 von Jhering. A little in front of this section the kidney tubules take up a 

 distinctly lateral position. 



D ; ji.g. ; b.r. ; k.t. \ r.o. as in fig. 1. 



A, auricle ; V, ventricle ; h.v., branchial vein ; b.a., branchial artery ; 

 ji.c, pericardial cavity ; l.n.., lateral nerve (pallial) ; f.n., pedal nerve ; 

 F, foot ; A.C., alimentary canal ; g.g., generative gland ; b.c, body cavity ; 

 k.c. see h..t. ; p.k.d., part of kidney duct which in fig. 1 is hidden from view 

 by D. 



caeca, but runs backwards as a simple duct distinguishable 

 by its brown colour, which is due to a deposit of colouring 

 matter in its walls. On reaching the level of the bladder- 

 like dilatation of the kidney duct first described, it applies 

 itself to the dorsal inner wall of that structure as far back 

 as the level of the last gill. At this point, which marks the 



