436 J H- FULLARTON, 



and (liffereuces iu species may account for much, although hardly for 

 such divergences in his and my observations. He gives a drawing 

 (tab. 13, fig. 20 b & a) of the posterior part of T. mariana, showing three 

 pairs of testes in the last three segments, and two pairs of segmental 

 organs in the first two of these. He evidently follows Carpenter 

 & Claparkde in interpreting his three pairs of "birnförmige Schläuche" 

 as testes ("Hoden"), but I am puzzled to understand the coexistence 

 in two of them of segmental organs, and the absence of these in a 

 third as his figure shows. 



Female generative organs. The female generative pro- 

 ducts were seen by the earliest observers, for it is fairly certain that 

 "kleine Kügelchen" of Eschscholtz referred to ovarian cells, and QiiOY 

 & Gaimari) saw "ovules", both in the cavities of the parapodia, 

 and in the body -cavity alongside of the digestive tube. Busch 

 also mentions characteristic "Eier", but Leuckart & Pagenstecher 

 were the first to observe the female generative organs, as well as 

 the paired genital openings in the female, and other observers 

 since have also seen them. In all the females , which I obtained, 

 ovarian cells were present, in the smaller and tail-less forms in the 

 position where they originate, and in ripe adults, both in that place 

 and also separated from the mother-tissue. In living animals the 

 free ovarian products were seen circulating in the body-cavity, between 

 the intestine and the body-wall, and in its lateral continuations, from 

 the frontal horn-like lobes and the base of the appendages from which 

 the styliform tentacles arise, to the last pair of bi-ramous parapodia. 

 This circulatory motion was effected chiefly by the peristaltic move- 

 ments of the intestine, but in the region of the head, at least, there 

 were also smaller currents promoting circulation, which could only be 

 accounted for by the action of the cilia of the endothelium as Greeff 

 has already noticed in T. Jcefersteini. The large ripe eggs. Fig 10 ov, 

 when pressed between the body-wall and the intestine and against 

 each other, were continually altering their shape owing to the pressure 

 exerted. In this way they were made to assume an oval shape, and on 

 the relaxation of pressure they returned to their normal spherical outline. 



The ovaries, like the testes , occupy a position in the forks 

 of all the lateral parapodia, Fig. 10 o, but are wanting in the para- 

 podia, which are indistinctly bi-ramous and sub-ventral. Before the 

 formation of generative tissue, it is imjiossible to distinguish the endo- 

 thelium from which it ultimately arises, from the rest of the endo- 

 tholiurn lining the body-cavity or fnmi that porticm of the endothelium 



