OBSERVATIONS ON ORIODRILUS LAOUDM. 555 



cuticle, but never grows closely with it, so that the sperraato- 

 phore very easily falls away. That the great areola round the 

 male pore and the swelling in front of it play an important part 

 in copulation cannot be doubted, for, after the laying of the 

 eggs, these structures immediately decrease in size. In speci- 

 mens which I collected at the end of June I could find neither 

 the swellings nor the areola, and in some even the male pore 

 also had become indistinct. 



As to the time of sexual maturity of Criodrilus nothing 

 positive is known. According to Vejdovsky the maturity 

 seems to be attained in the months of June and July, since 

 Hatschek found the cocoons with segmented eggs and embryos 

 in the middle of June, whilst Hoflfmeister mentions the worms 

 furnished with *' pseudo-spermatophores ^' at the beginning of 

 July; Vejdovsky himself has not studied mature worms. My 

 researches, however, extending over many years, show that the 

 embryos escaping from the egg in summer may attain sexual 

 maturity as early as February or March in the following year ; 

 indeed, in the most favorable seasons copulation may even 

 take place in these months. Copulation and egg laying take 

 place almost certainly in June, since I have found at the 

 beginning of July of this year no cocoons with embryos. The 

 best sign of maturity are the large and very striking sperma- 

 tophores, which are to be found regularly from March to the 

 end of May, certainly not later. The embryos escape from the 

 cocoons in May, June, and July ; at the end of the latter 

 month I have collected only empty egg cases. At first the 

 young worms are to be found amongst the thick roots ol 

 aquatic plants, only later in the mud, where they pass the 

 winter and attain maturity. The clitellum, so very character- 

 istic of the Lumbricinse, is, as Hofi'meister rightly insisted, 

 absent. I have for many years collected these worms at all 

 seasons, yet I have found no trace of a clitellum, nor of the 

 so-called " tubercula pubertatis ;" the great glandular areola 

 of the male genital pore appears to replace the clitellum. 



The egg cases of the Lumbriciuse are known as roundish- 

 oval chitinous capsules with pointed appendages^ and are 



