554 MONTGOMERY— MORPHOLOGY OF THE [April 24, 



Species (I also have looked for them in vain in a number of Amer- 

 ican species). In the female there is a pair of them discharging 

 into the oviduct; each is a broad spade-shaped organ composed of 

 three cells, the free end branched dendritically, each finest sub- 

 division of which terminates in a perforated membrane bearing 

 on the luminal side a tuft of long cilia; there are about five to six 

 hundred of these terminal flames to each nephridium, though the 

 whole organ it will be recollected is composed of only three cells. 

 The Acanthocephala are specially characterized by the small number 

 but great degree of specialization of their cells. In the male the 

 nephridia open into the ductus ejaculatorius, and are similar to 

 those of the female save that the terminal flames are less numerous. 

 Kaiser supposes that in the smaller species lacking these organs the 

 oviduct is excretory, since in them the uterus bell is open to the 

 body cavity. 



They arise conjointly with the genital ducts from the ectoblast. 



9. Ch^tognatha. 



No excretory organs were found by Hertwig (1880), while 

 Grassi (1883) suggests that a pair of small glands opening at the 

 junction of the head and prepuce may be urinary. 



The genital ducts are not comparable with nephridia because 

 they do not develop until maturity, and because the vasa deferentia 

 are ectoblastic and the oviducts are outgrowths of the ovaries 

 (Doncaster, 1902). 



10. KlNORHYNCHA. 



The genus Echinoderes exhibits one pair of short, pyriform 

 canals, ciliated throughout, with enlarged closed inner ends, that 

 open separately and dorso-laterally (Reinhard, 1887). 



II. Nematoda. 

 As first made known by Anton Schneider (1866) and confirmed 

 by most subsequent writers there is usually an excretory duct in 

 each lateral line (though one may be wanting) that extend from 

 the posterior region of the body to the oesophagus, where they con- 

 verge and open by a single median nephridiopore. The inner ends 



