478 PATTEN AND HAZEN. [Vol. XVI. 



Eight smaller nerves arise from the roots of the pedal nerves 

 and supply the coxal muscles at the base of the coxite. There 

 are two of these nerves to each lobe, one on either side (PI. 

 XXVIII, Fig. 83, exM^-""). The third, fourth, and seventh 

 nerves pass directly through the stolon ; the second, fifth, 

 sixth, and eighth nerves pass over its dorsal, and the first 

 over its ventral, side. 



No branches could be found running from these nerves 

 into the lobes, although sections show the presence of numer- 

 ous fine nerve bundles ramifying through the lobes in all 

 directions. 



In sections of the adult gland one may distinguish five con- 

 centric layers, each layer containing nephridial tissue in differ- 

 ent stages of development. Beginning at the center of the lobe, 

 we have in order: (i) large collecting tubes (PI. XXVI, Fig. 

 54); (2) small clear-walled tubules. Fig. 53; (3) tubes lined 

 with granular cells. Fig. 52 ; (4) chains of vacuolated cells, 

 Fig. 51; (5) large granular cells. Fig. 50. 



The large granular cells are very numerous on the ventral 

 and dorsal sides of the nephric lobes (PI. XXVI, Fig. 49, g.c). 

 Under a higher power two or three nuclei are sometimes seen 

 in a single cell. In borax carmine and Lyon's blue, or in 

 Delafield's haematoxylin and eosin, the cell wall takes a dark 

 stain and appears as a fine thread among the unstained gran- 

 ules. Wedged in between them were occasional bunches of 

 from five to ten or more small dark-colored cells, probably 

 blood corpuscles (PL XXVI, Fig. 50, b.g.c). 



Small bundles of nerve fibers are abundant in the granular 

 tissue, especially on the median dorsal side of the nephridial 

 lobe (PI. XXVI, Fig, 50, n). In fresh specimens this tissue 

 has a dull orange color and resembles adipose tissue. A layer 

 of loose connective tissue forms an indistinct boundary between 

 the cells just described and the true nephridial cells. 



The latter form the layer marked h.c. in PI. XXVI, Fig. 49. 

 It consists of small cells with large dark nuclei (PI. XXVl, Fig. 

 51). The innermost cells are vacuolated, and have fine granu- 

 lar protoplasm on the periphery, and some have united end 

 to end to form delicate intracellular tubules like those seen in 



