200 



FILTER-BED NEMAS 



The . excret 



pore is at the li 

 The submedi 



em'pty 1 ' oppos 



remarkable in this respect. It has lit- 

 tle difficulty in swallowing nemas half 

 as wide as itself; and the partly di- 

 gested remains of several such may 

 sometimes be seen in its intestine. 

 (See Fig. 3.) 



IRONUS Bastian 1865 

 4. Ironus longicaudatus de Man. 



.! _ 7.1 15. '36"3 66. 

 /1.6 1.9 2. 2.2 1.2 



As regards the pronounced dorso- 

 ventral differences in the intestine of 

 Ironus longicaudatus, when specimens 

 of this species are stained in acid car- 

 mine it is noticeable that the large 

 granules characteristic of the dorsal 

 side take the stain. From an exami- 

 nation of living specimens one would 

 think these granules 

 probably fatty in their leJkt./JS 

 nature. The fact that 



.11 

 they Stain as they do 



seems to exclude this 

 supposition. 



No Sperm keen. In back. The 

 spite of very careful ex- &* o 

 amination I was unable 

 to discover spermatozoa 

 in the females of this 

 species. Nevertheless I 

 am strongly inclined to 

 think that further in- 

 vestigation will reveal 

 the presence of sperma- 

 tozoa, and show that this 

 species also is syngonic. 

 I have seen no males. 



I believe the food- 

 habits of Ironus longi- 

 caudatus to be much the 

 same as those of Ironus 

 ignavus, but having had 

 less opportunity to in- ^ 

 vestigate them I have '* 

 fewer data from which *" 

 to form an opinion. 



Habitat: Washington * 

 filter-beds; sometimes v 

 abundant. Quite active, ;/ 



ay' 

 rail 



xl.ii 



very much from 

 thevantral. 



tfjer 



r! a 



