180 



THE ANNELIDES. 



^ 167. 



§167. 



The genital organs of the Lumbricini are very diflScult of dissection : 

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

 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 

 pyriforra 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 beerr- 

 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, eorgs and ecfg-g-erms, and oujjrht therefore t& 

 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 liave been figured by Montis:re 

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

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

 Tab. III. fig. 2). With Saenuris, and Nnis, 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 

 variesata, and Nais proboscidea. From H. 

 Meckel's late researches upon the very compli- 

 cated genital apparatus of Z/um/^rfc«.? terrestris^ it 

 appears that there are three pairs of seminal vesi- 

 cles and testicles ; these last being intimately joined 

 with as many ovaries (^Mailer's Arch. 18-14, 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 semiuales ; see Mor- 

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

 in his Zeitsch. f. Pliysiol. 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 Diigis 

 appears to represent (Ann. d. Sc. Nat. XV. 1828, 

 p. 328, PI. IX. fig. 2, or Isis, 1830, Taf. III. 

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

 invaginated in the oviduct. Many observers have 

 gone so far as to think that the eggs having escaijed 

 from the ovary, and fallen into the cavity of the 

 body, pass gradually to its posterior i)ortion, and 

 are there evacuated through invisible openings. 

 On this account, several of them have taken for 

 eggs and embryoa, 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. 182;j, I'l. CXLIX. 



I have always lnv/n ustcmished that, at the epocll 

 of procreation with Saenuris, Eunxes, and Nais, 

 the two anterior genital ojieniiigs should communi- 

 cate with two caeca which contain sperm and long 



bundles of spermatic particles, but never their cella 

 of development. Duges has made a similar obser- 

 vation with his Nais ßliformis (Ann. 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 h& 

 unhesitatingly regards them as testicles (fVieg~ 

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

 fig. 3). Never having seen any connection betweer» 

 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 Receptacula 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 dir Kcgenwürmer,. 

 1845, p. 15) of the copulatory act with Liinihricus- 

 agricola, it would a])pear that the sperm remains 

 equally distant from the female organs, being re- 

 ceived into s])ecial fossae, which corresi>ond per- 

 haps to the Receptacula seminis. Nais probos- 

 cidea, although having a pair of genital cipi-nings,. 

 has only one testiculo-ovarian canal, both of which 

 although invaginated, have a very active and inde- 

 pendent peristaltic action. They are bifurcated an- 

 teriorly. See Gruit/iuisen (Nov. Act. Acad. Nat. 

 Cur. XI. p. 246, Tab. XXXV. fig. 4, 5), who hiu» 

 very correctly perceived the eggs in the bottom of 

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

 nated testicular canal. 



3 With L-umhrinus olidu.t, ,he two copulatins' 

 individuals seize each other so iightly ny their col- 

 lars, that each of these animais completely envel- 

 ops the other by this organ ; see Hoffmeistcr, in 

 fViegmanii\i Arch. 1843, I. p. I'JO, and. De ver- 

 mibus quibusdam, Tab. I. fig. 30. 



