440 EDWIN S. GOODRICH. 



Appelof, of l^ergen, and Dr. Thiel, of Stockholm, for other 

 specimens of the same species. 



Glycera. 



In this genus the " ciliated organ "" is so closely connected 

 with the true nephridium, although it does not actually open 

 into its lumen, that the two structures have been confounded 

 by Ehlers (2), the only observer who gives an account of the 

 excretory organs of Glycera. 



The nephridium, the ciliated organ, and a peculiar organ 

 which I shall call the nephridial sac, are all united into a 

 single structure which may for convenience be called the 

 nephridial complex. Ehlers, in his well-known work on the 

 Polychseta, described the position of this nephridial complex 

 on the anterior surface of the septum accurately enough ; but 

 he failed to make out its real structure, partly no doubt owing 

 to the fact that he studied it in spirit specimens only. Wiiat 

 he describes as the duct of the segmental organ would appear 

 to be, judging from his figure, the extended outer lip of the 

 ''ciliated organ; " and what he took for an internal opening 

 may perhaps be another portion of the same. The nephridium 

 itself escaped his observation ; and, indeed, it is very difficult 

 to make out in preserved specimens. 



Before describing these organs in detail it is best to give a 

 "^eneral account of tiieir distribution, shape, and mutual re- 

 lations. 



On examining a fresh specimen of Glycera siphouostoma 

 which has been opened up dorsally, and from which the gut 

 has been removed, small round bodies can be seen on either 

 side near the base of each parapodium, attached to the front 

 face of the septum, and lying below and partially hidden by the 

 bundle of chgetge with its muscles (fig. 1). One pair of tiiese 

 bodies occurs in every segment excepting the first few and the 

 last one or two ; in a full-grown specimen they appeared to be 

 absent in the first twenty segments. Each body constitutes 

 what I have called the nephridial complex, consisting of a 

 hollow sac, the "nephridial sac," forming a flatteued disc-like 



