590 OLIGOCHAETA 



I refer this species, with some doubt, to the genus Eudriloides. When I first 

 examined it I was inclined to regard it as a Notykus. The similarity to that genus 

 is in the presence of a sac which encloses the ovaries and the distal end of the 

 spermathecal sac. The resemblance, however, to MICHAELSEN'S description and figure 

 of the female generative organs of Notykus is possibly only apparent ; for in the 

 present species the sac is merely produced by a junction between the septa xii/xiii 

 and xiii/xiv. It is not a separate sac as it probably is in Notykus ; but, as MICHAELSEN 

 has remarked in describing Notykus emini that he was unable to make out fully the 

 generative organs in that species, it is a possibility that must not be lost sight of 

 that that worm is also an Eudriloides. The principal argument against placing 

 the present species in the genus Eudriloides is because it has in the epidermis 

 the ' Pacinian bodies ' which do not occur in other forms. Another difference is 

 the fact that the two spermiducal glands are contained within a common sheath and 

 that they are covered by a thin peritoneal layer only instead of by the thick muscular 

 layers that are found in, at any rate, the two last species of Eudriloides. The form 

 of the penial setae is unfortunately unknown. 



Genus REITHKODRILUS, MICHAELSEN. 



DEFINITION. Setae strictly paired. Male pore on XVIII. Spermiducal gland 

 single, with one sac of penial setae. Spermathecal pore on XIII. 



This genus is unfortunately only known by a single, and that an incompletely 

 mature, individual. The above definition, however, is sufficient to distinguish 

 Reithrodrilus from any other Eudrilid. 



The prostomium has no dorsal prolongation. 



The alimentary canal has a gizzard in v. Nothing is said about the calciferous 

 glands or other structures connected with the alimentary canal. There is only a single 

 spermiducal gland and a single sac of penial setae corresponding to this. The two 

 segments in front of that which bears the male pore, i. e. the fifth, sixteenth, and 

 fifteenth, have each a single median copulatory papilla ; with this papilla is connected 

 a pair of sacs of setae precisely similar to the penial setae. Of the female organs 

 only the spermathecal sac was seen. This is a long sac extending back as far as 

 the male pore. 



Reithrodrilus minutus, MICHAELSEN. 

 B. minutus, MICHAELSEN, JB. Hamb. wiss. Anst. ix, 1891, p. ai. 



