180 



THE ANNELIDES. 



^ 167. 



§ 167. 



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

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

 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, enrs-s and e2;o;-2;erras, and ouoiht 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- 



i With Lumhricus terrestris, the two anterior 

 genital openings are male, and the two posterior, 

 female. These have been figured by Montisre 

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

 restr. Tab. I. fig. 2), and by Morren (loc. cit. 

 Tab. III. fig. 2). With Saenuris, and Nais, I 

 have also found these two pairs of genital openings. 



2 This invagination of the testicle in the ovary 

 has been distinctly observed by me with Saenuris 

 variegata, and Nais proboscidea. From H. 

 Meckel's late researches upon the very compli- 

 cated genital apparatus of Lumhricus terrestris, it 

 appears that there are three pairs of seminal vesi- 

 cles and testicles ; these last being intimately joined 

 with as many ovaries (Mu/Zer's Arch. 1814, p. 

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

 the testicles and ovaries are also invaginated, and 

 that the vesicles which have usually been taken for 

 testicles are only vesiculae semintUes ; see Mor- 

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

 in his Zeitsch. f. Physiol. V. p. 154, 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. So. Nat. XV. 1828, 

 p. 328, PI. l.X:. fig. 2, or Isis, 1830, 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, § 145, note 1 ; and E. Home, Lect. on 

 Comp. Anat. IV. 1823, 1>1. CXLIX. 



I have always been astonished that, at the epucli 

 of procreation with Sxcnuris, Euaxes, and Na'is, 

 clie two anterior g jniial openings shuuld communi- 

 cate with two caeca whicli contain sperm and long 



bundles of spermatic particles, but never their cells 

 of development. Dugis has made a similar obser- 

 vation with his Nais Jiliformis (Aim. d. So. 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 lie 

 unhesitatingly regards them as testicles iJVieg- 

 mann's Arch. 1845, I. p. 32, Taf. III. fig. 2, aa. 

 fig. 3). Never having seen any connection 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, while 

 the anterior caeca, which are filled at certain times 

 with sperm, are two isolated Rcceptacula seminis. 

 During the mutual copulation, the sperm will pass 

 from the testicles into these reservoirs, in order to 

 be used during the subsequent deposition of the 

 eggs. 



From Hoffmeister's description (Die bis jetzt 

 bekannt. Arten aus der Familie der Kegenwiirmer, 

 1845, p. 15) of the copulatory act with Lujnbricus 

 agricota, it woulil appear that the sperm remains 

 equally distant from the female organs, being re- 

 ceived into special fossae, wliich correspond per- 

 haps to the Receptacula seminis. Nats probos- 

 cidea, although having a pair of genital openings, 

 has only one testiculo-ovarian canal, biitl> 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. 246, Tab. XX.XV. fig. 4, 5), who has 

 very correctly perceived the eggs in the bottom of 

 the ovarian sac, but not the nature of tlie invagi- 

 nated testicular canal. 



3 With Lumbricus olidus, the two copulating 

 individuals seize each other so tightly by their col- 

 lars, that each of these animals completely envei- 

 ojis the other by this organ ; see Hoffmeister, in 

 fViegmann's Arch. 1843, I. p. 190, and, De ver- 

 mibus quibusdam, Tab. I. fig. 30. 



