112 Illinois State Laboratorij of Natural History. 



The nephridia open into the coelom by a conspicuous broad, 

 shallow, bi-lobed, ciliated funnel (PI. VII., Figs. 8 & 0) nearly 

 sessile on the anterior face of the dissepiment at about the level 

 of the nerve cord. The larger lobe of the funnel is composed 

 of a single layer of cylindrical cells arranged fan-like, and each 

 covered at its outer end by a dense brush of long and very fine 

 cilia. From this funnel a short tube narrows rapidly backward 

 to the dissepiment, through which it is continued into a narrow 

 lobe of the so-called fatty body of the somite behind (PI. VII., 

 Fig. 10). These bodies, composed of irregular masses of large 

 cells, contain, according to Leydig,* delicate contorted tubes 

 representing the glandular portion of the nephridia, — a fact 

 difficult to demonstrate positively in prepared slides. They 

 extend upwards beside the alimentary canal, in iaimediate prox- 

 imity to the chlorogon layer, their upper end sometimes reach- 

 ing the dorsal vessel. Below, a slender lobe extending down- 

 wards and inwards is supported by one of the setal muscles, 

 which is inserted on the middle line of the ventral body wall. 

 Another lobe extending downwards and outwards, contains the 

 large excretory duct, which passes from the dorsal surface of 

 the intestine with an S-like curve to the body wall (PI. VI., 

 Fig. 2), where it is rapidly narrowed to a minute tube, which, 

 passing through the body wall, opens, with a slightly expanded 

 orifice, upon the surface about a tenth of a millimeter in front 

 of the seta and quite outside the setal sheath. This orifice, in 

 the living worm, is frequently marked by little accumulatious 

 of excrete matter, and the tube can be traced a short distance 

 inward by the thick cuticular lining of its terminal part. The 

 first nephridium appears in the ninth segment, and the first 

 ciliated funnel in the eighth. These striu-tures are, however, 

 rudimentary in the first six segments in which they occur, the 

 fatty bodies being reduced to narrow masses of connective- 

 tissue nuclei which extend up in a single band beside the ali- 

 mentary canal, immediately behind the dissepiment, and the 

 funnel not being bi-lobed and not always ciliated. No duct or 

 external opening is distinguishable in these anterior nephridia.f 



* Archiv f. Mikrosk. Auat. I., p. 283. 



t The segments in wliieli tbese incomplete nephridia occur, are, 

 according to lieddard, tliose in which th(3 sexual organs are situated 

 in the sexually mature worm. 



