180 



THE ANNELIDES. 



§ 167. 



§167. 



The genital organs of the Lumbricini arc very difficult of dissection ; 

 for often those of both sexes are intimately united together into a conunon 

 mass. It is certain, however, that the male and female orifices are always 

 in pairs and situated at the anterior extremity of the body, near the ven- 

 tral median line.*'* 



These orifices communicate with more or less numerous glands, sacs, and 

 pyriform or cylindrical vesicles. 



Their nature as testicles, ovaries or sperm-receptacles, is known only by 

 their contents. As yet it has been possible to trace only very imperfectly 

 their excretory ducts. With some, two of these caecal organs have been 

 observed intersuscepted in each other. The internal one contained sperm- 

 atic particles, and should therefore be regarded as a testicle ; while the 

 outer one contained at its base, eggs and egg-germs, and ought therefore to 

 be taken for an ovary.*-'' 



The larger Lumbricini appear to be without copulatory organs, the 

 collar situated back of the genital orifices, taking their place. With many, 

 it is situated chiefly on the back, but terminates on the belly with two long 

 lateral swellings, which, during coition, seize those of the other individ- 

 ual.''^* This collar, moreover, is composed of a mass of glandular follicles, 

 which copiously secrete, during the sexual period, a white, viscous liquid. 

 It is then very fully developed, but at other periods it is scarcely visible. 

 The belt which is developed near the genital openings of the smaller Lum- 



1 With Lumbricus terrestris, the two anterior 

 genital openings are male, and the two posterior, 

 female. These have been figured by Montigre 

 (loc. cit. fig. 2, a. c), Leo (De Struct. Lumbr. ter- 

 restr. Tab. I. fig. 2), and by Morrcn (loo. cit. 

 Tab. III. fig. 2). With Saenuris, and iVai,?, I 

 have also found these two pairs of genital openings. 



2 Tliis invagination of the testicle in the ovary 

 has been distinctly observed by me witli Saenuris 

 variegata, and Na'is proboscidea. Vrom H. 

 Meckel's late researches ujion the very compli- 

 cated genital apparatus ol Lumbricus terrestris, it 

 appears that there are tliree pairs of seminal vesi- 

 cles and testicles ; these last being intimately joined 

 witli as many ovaries (Muller's Arcli. 18i4, p. 

 480, Taf. XIII. fig. 12). It is probable tliat here 

 the testicles and ovaries are also invaginated, and 

 that tlie vesicles wliich have usually been taicen for 

 testicles are only vesiculae seminales ; see Mor- 

 ren, loc. cit. p. 175, Tab. VII.-X. and Treviranus, 

 in his Zeitsch. f. Physiol. V. p. 151, Taf. VII. How- 

 ever, as yet I have been unable to trace to their ter- 

 mination, the excretory ducts of the testicles and 

 ovaries which are invaginated together. 



This point is all the more difficult, for, as Dugis 

 appears to represent (Ann. d. Sc. Nat. XV. 1S28, 

 p. 328, PI. IX. fig. 2, or Isis, 18130, Taf. III. 

 Tab. 9, fig. 2), the vas deferens is probably 

 invaginated in the oviduct. Many observers have 

 gone so far as to think that the eggs having escaped 

 from the ovary, and fallen into the cavity of the 

 body, pass gradually to its posterior portion, and 

 are there evacuated through invisible openings. 

 On this account, several of them have taken for 

 eggs and embryos, the collections of horny spines, 

 and vibrios, which are often found in these animals. 

 See above, § 115, note 1 ; and E. Home, Lect. on 

 Comp. Anat. IV. 1823, PI. CXLIX. 



I have always been astonished that, at the epoch 

 of procreation with S'cenuris, Euaxes, and JSais, 

 the two anterior genital openings should communi- 

 cate with two caeca which contain sperm and long 



bundles of spermatic particles, but never their cells 

 of development. Dugis has made a similar obser- 

 vation with his Nats Jilifnrmis (.\nu. d. Sc. Nat. 

 loc. cit. p. 320, PI. VII. fig. 2), only he does not 

 specify the contents of the organs. Menge, also, 

 has observed these two caeca with Euaxes, but he 

 unhesitatingly regards them as testicles (fVieg- 

 mann's Arch. 1815, I. p. 32, Taf. III. fig. 2, aa. 

 fig. 3). Never having seen any comiection between 

 these caeca and the testicles behind them, I am 

 disposed to think that the two posterior genital 

 openings of some Lumbricini, are the common ori- 

 fices of the invaginated testicles and ovaries, wliile 

 the anterior caeca, which are filled at certaiu times 

 with sperm, are two isolated Receptacula seminis. 

 During the mutual copulation, the sperm will pass 

 from the testicles into these reservoirs, in order to 

 be used durmg the subsequent deposition of the 



From Hn^^meister's description (Die bis jetzt 

 bekanut. Arten aus der Familie der Hegenwiirmer, 

 1815, p. 15) of the copulatory act with Lumbricus 

 agricola, it would appear that the sperm remains 

 efiually distant from the female organs, being re- 

 ceived into special fossae, which correspond jier- 

 haps to the Receptacula seminis. Nais probos- 

 cidea, although having a pair of genital openings, 

 has only one testiculo-ovarian canal, both of whioli 

 although invaginated, have a very active and indi.- 

 pendent peristaltic action. They are bifurcated an- 

 teriorly. See Gruithuisen (Nov. Act. Acad. Nat. 

 Cur. XI. p. 216, Tab. XX.W. fig. 4, 5), wlio lias 

 very correctly perceived the eggs in the bottom of 

 the o\'arian sac, but not the nature of the invagi- 

 nated testicular canal. 



•'i With Lumbricus olidus, the two copulating 

 individuals sfeize eacli other so tightly by their col- 

 hirs, that each of these animals completely envel- 

 ops the other by this organ ; see HoJ/meister, in 

 tVicgmann's Arch. 1843, I. p. 190, and, De vei- 

 mibus quibusdam. Tab. I. fig. 30. 



