378 PROCEEDINGS OF THE ACADEMY OF [May, 



Nephridial system. — The whole iiephridial system of one side of the 

 body is shown in fig. 9, and a portion of it from dorsal view in fig. 10. 

 Into the posterior end of the cloaca (CL)opens the unpaired contractile 

 vacuole {Con.V.); and into this a long elongate unpaired sac with dis- 

 tinct outer lining and containing a convoluted tube with wide, pulsatile 

 kmien, the common terminal canal. At the free end of the latter unite 

 with it the two longitudinal canals of the nephridia. Each of these 

 passes forward latero-ventrally to al^out the level of the stomach 

 glands, and there becomes much convoluted so that the exact course 

 is difficult to follow; but through all these convolutions it remains a 

 single tube with distinct walls. Each lateral canal then turns dorsad 

 to about the position of the cerebral ganglion where it again Ijecomes 

 convoluted ; its diameter is greatest in this portion of its course. At 

 this anterior end the ductules are given off to the flame cells, and, as 

 fig. 9 shows, one ductule passes forward and divides into five ductules, 

 each ending in a flame cell {Fl.C. 1, Fl.C. 2). A second ductule passes 

 posteriorly and ends in a flame cell (Fl.C. 6) placed near the stomach. 

 In one individual I saw two other flame cells {Fl.C. 7, Fl.C. 8) placed 

 near the sixth flame cell, but their connections with the ductules of the 

 nephridial system I did not find. As the dorsal view, fig. 10, shows, 

 in front of the cerebral ganglion a transverse commissure connects the 

 ductules of the two sides of the body. Each flame cell (fig. 15) bears 

 internally a flame of long cilia, and appears completely closed from the 

 body cavity. The lumen of all the ductules and the main canals is 

 intracellular, and cilia are found only in the flame cells. The whole 

 nephridial system is exceedingly distinct in life, provided the animal is 

 well expanded. 



Dorsal glandular organ. — On the dorsal side, at the junction of the 

 corona with the trunk, lies a large mass (D.Gl., figs. 9, 10) of clear 

 vacuolar structures, which has been heretofore regarded by most 

 writers as the brain. It is composed of clear transparent globules, 

 varies in size in different individuals, and becomes shrunken by the 

 action of alcohol. Nuclei are to be seen at its margins, particularly 

 posteriorly, but I was unable to determine whether each of its com- 

 ponent globules represents a cell. This organ is closely attached to 

 the dorsal hypodermis around the dorsal sense-organ {D.Sens.O., 

 fig. 9), and is penetrated by the nerves which pass to the latter from 

 the cerebral ganghon (Cer.) ; it has no connection with the alimentary 

 tract. The functional significance of this organ is whoHy obscure, 

 and I have supposed it to be glandular simply on account of its con- 

 nection with the hypodermis and the dorsal sense-organ. It is not 



