NEPHRIDIA OF CERTAIN EARTHWORMS. 397 



On the Occurrence of numerous Nephridia in 

 the same Segment in Certain Earthworms, 

 and on the Relationship between the Excre- 

 tory System in the Annelida and in the 

 Platyhelminths. 



By 



Frank. I-:. Beddard, M.A., 



Prosector to the Zoological Society of London, and Lecturer on Biology at 

 Guy's Hospital. 



With Plates XXX and XXXT. 



Acanthodrilus multiporus, F. E. B. 1 



The nephridia of this worm differ in their appearance from 

 those of any other species of Acanthodrilus at present 

 known. In a dissection of the worm the nephridia can be 

 recognised as a series of glandular tufts closely adherent to the 

 body wall and to the intersegmental septa ; each of the eight 

 setfe often appeared to have a nephridial tuft specially related 

 to it : thus by dissection there seemed to be eight separate 

 nephridia in each segment. This, however, is not invariably 

 the case, and in the anterior segments no relation between 

 the setse and the nephridia could be detected by dissection. 



I have also studied these organs by transverse and longi- 

 tudinal sections. 



By these means I have been able to ascertain that there 

 are more than one pair of nephridiopores in each seg- 

 ment ofthe body. 



These observations depend upon the study of very well- 

 1 ' Proc. Zool. Soc.; 1885. 



