556 MONTGOMERY— MORPHOLOGY OF THE [April 24. 



either the genital ducts or the intestine, since the thick cuticula on 

 the surface of the body is hardly permeable. 



The gland of the larva construed by Villot (1874) as an 

 excretory organ has been considered by me (1904) to be rather 

 a poison gland ; I have shown that its body develops as an abstriction 

 of the entoblast, and that its duct opens at the base of the pro- 

 boscideal stilets ; it is completely closed from the body cavity and 

 does not possess cilia. - 



13. ECTOPROCTA. 



For the Phylactolsemata the fullest description is that of Cori 

 (1893, Cristatella) , according to whom there is a nephridium just 

 above the anus, between the body wall and the peritoneum, con- 

 sisting of two ciliated nephrostomes opening into the coelom, con- 

 necting with an enlarged sac that has a single nephridiopore near 

 the cerebral ganglion. He proved experimentally that lymphocytes 

 ingest waste particles, and then are discharged by this organ. 



In the Gymnolffimata there is in some species an organ discov- 

 ered by Hincks (1880), and more fully described by Prouho (1892) 

 who names it the " organe intertentaculaire " ; this occurs only in 

 sexual individuals, is primarily a genital duct, and is a ciliated 

 canal with an inner nephrostome. In most Gymnolsemata special 

 excretory organs are absent (Ostroumofif, 1886, Harmer, 1891). 

 Harmer concludes from injection experiments that excretion is per- 

 formed " partly by the cells which I have described as leucocytes, 

 partly by the walls of the alimentary canal, and partly^ by the 

 funicular tissue," while he and Ostroumoff have proved that the 

 formation of the " brown body " and the death of the polypid is 

 due to an accumulation of waste substances especially in the 

 intestine. 



The larvae lack excretory organs, and the development of those 

 of the adult has not been described. 



14. SiPUNCULIDA. 



There are as a rule two " excretory tubes," but within the same 

 genus either two or one may occur. In most cases each of these has 



*In the marine Nectonema, that shows some similarity to the diplobiotic 

 Gordiacea, excretory organs are unknown. 



