758 FRANK E. BEDDARD, 



ductive Organs are in more than one respect remarkable ; the sperm- 

 sacs lie in segments XI and XII as usual, but are not so voluminous 

 as is often the case ; they are vei-y niuch less capacious than are the 

 sperm-sacs of P. sieholdi for exaniple ; the four sacs form one con- 

 tinuous structure as is shown in the acconipanying figure (Fig. ü). The 

 testes I did not succeed in finding, as I did not examine into the 

 structure of the animal by means of microscopical sections; the 

 testes of earthworms are as a rule difficult to see without applying this 

 method of investigation. As the septum between segments IX/X is 

 wanting, the testes must be, as they sonietimes are aniong earthworms 

 — e. g. Acanthoärilus amiectens — attached to the posterior instead 

 of to the anterior wall of their segment. 



The ciliated rosettes (see Fig. 7) are inclosed within the sperm- 

 sacs ; the vas deferens, where it issues from the septum bounding the 

 Xllth segment posteriorly, is somewhat dilated. The two vasa de- 

 ferentia join almost immediately and pass along the body wall in an 

 almost straight line to the point of opening on to the exterior. The 

 niost noteworthy structural character of this new species of Perichceta 

 concerns the way in which the vasa deferentia open. At the present 

 moraent no exception is known to the rule that the vas deferens in 

 tlie Perichatidce, and for the matter of that in all the genera belonging 

 to my family AcanthodrilidcB ^) terminates in, or near, a partly mus- 

 cular and partly glandulär atriuni ; it is only in the Geoscolicidce and 

 Lumhricidff; that a terminal coi)ulatory organ is not usually found. 

 I was therefore much surprised to find not the least trace of an 

 atrium in the first specimen of Perichceta roJcugo that I dissected. In 

 describing the external characters I have already pointed out the 

 apparent absence of external male pores, which are so exceedingly 

 obvious in all other Perichcetidfe even when not fuUy raature. My 

 specimens of Pericliceta roJcugo were not only quite mature as regards 

 external characters (presence of clitellum etc.), but the internal Or- 

 gans of generation were also ripe. Still I thought that there might 

 be something abnormal about this particular worm, and therefore 

 proceeded to dissect the remaining specimens in order to discover if 

 they were furnished with atria ; in none of them however was there 

 the faintest sign of an atrium even of the most rudimentary description. 

 It is therefore clear that this Perichceta differs from all the 



1) The Classification and distributioii of eartliwornis, in: Proc. Roy. 

 Phys. Soc. 1891. 



