558 MONTGOMERY— MORPHOLOGY OF THE [April 24, 



16. PliORONIDEA. 



In the adult just behind the transverse septum Cori (1890) 

 found a pair of ciliated canals with open nephrostomes, and deter- 

 mined that their function is both genital and urinary. In Phoronis 

 australis Benham (1889) found that each tube has two nephro- 

 stomes, and a similar relation was discovered by Cowles (1905). 



There is quite general agreement that the larval nephridia are 

 ectoblastic (Ikeda, 1901, Longchamps, 1902, Shearer, 1906, Cowles, 

 1905) ; from a nephridial pit at the posterior end grow out the two 

 canals whose cavity is intercellular. The observers already cited 

 together with Caldwell (1882) and Goodrich (1903), in contradic- 

 tion to Masterman (1897), agree further that the nephridia of the 

 actinotrocha are closed at their inner ends from the blastocoel in 

 which they lie ; and Shearer, who gives the most complete account 

 of the development of these structures, shows that their inner ends 

 are closed by a group of solenocytes that represent outgrowths from 

 the tubes. Longchamps states that these larval organs persist into 

 the adult ; this is assumed by Shearer who decides that these canals 

 " acquire openings into the ccelom by means of ciliated funnels of 

 unknown origin " ; while Ikeda concludes : " We may assume that 

 the formation of the infraseptal nephridial funnels of the adult is 

 due to secondary outgrowths of the infraseptal portion of the 

 atrophied, larval nephridial canals." The only point not fully 

 decided is that of the origin of the funnels. 



17. Brachiopoda. 



According to the monographs of Van Bemmelen (1883), Bloch- 

 mann (1900) and Morse (1902) there is usually one pair of sup- 

 posed excretory organs, with nephrostomes and nephridiopores, 

 that serve as genital ducts; in Hcmithyris and Rhynchonella there 

 are two pairs. 



Nothing is known of their development, and there appear to be 

 no larval nephridia. 



18. ECHINODERMATA. 



Crinoidca. — Special excretory structures are unknown. 

 Ecliiuoidca. — The axial organ (ovoid gland) has been consid- 



