178 THE ANNELIDES. ^§ 165, 166. 



With (he Nemertini, and Branchiati, the sexes are upon separate individ- 

 uals, and the genital organs are composed simply of testicles and ovaries. 



§ 165. 



The structure of the genital organs of the Nemertini is yet quite obscure. 

 The few researches hitherto made only furnish the general result that the 

 sexes are separate. 



There are numerous glandular follicles situated laterally in the paren- 

 chyma of the body between the skin and the intestinal canal, which are 

 closely aggregated and serially arranged. 



With some individuals, these follicles contain eggs, and with others, 

 sperm. They ought, therefore, to be regarded as ovaries and testicles. 

 Each follicle opens separately upon the surface of the body.*^' There are 

 very contradictory statements as to whether these animals have, or have 

 not, copulatory organs. 



According to some Naturalists, the worm-like organ, concealed in a canal 

 extending along the back, and which, with both sexes, is often protruded 

 and moved actively about, ought to be regarded as an excitatory organ, — 

 although no connection between it and the testicles or ovaries, has as yet 

 been found. According to others, it is a proboscis unconnected with the 

 genital organs.*^' 



§ 166. 



The disposition of the genital organs of the Hirudinei and Lumbricini, 

 is essentially difierent. 



The first have only two simple genital openings, — one male, the other 

 female, both situated, one after the other, upon the median line of the ven- 



1 See Du^cs, Ann. d. Sc. Nat. XXI. 1830, p. 76, Po/i/stcmma armatiiin {Du^es, Ann. d. Sc. Nat. 

 PI. II. fi^. 5 {Poli/steinma (Prostomum) arma- loc. cit. p. 75, PI. II. ti^'. i>) Tetrastemma vari- 

 i«w7); JoAnsfon, Mag. of Zool. I. p. 532, PI. XVII. color {Orsted, Entwurf. &c. p. 23, Taf. III. fig. 

 lig. '2", 6'", PI. XVIII. fig. 3* {Nemertes and 41), and iVe7«cr<f.s (JoAnsion, Mag. of Zoul. I. p. 

 liorlasid) ; Orsted, Entwurf. einer Beschreib. d. 530, fig. 2 ; ^;/a?7-e/«i'-es, Regne anira. illustr. loc. 

 Hattwiimi. p. 22, Taf. III. fig. 41 (Tetrastemma cit. PI. XXXIV. tv/. 2, aud Kulliker, Verhandl. d. 

 varicolor) ; Kiil/i/icr, Verhandl. d. schweiz. na- schweiz. 4;c.) there is at the centre of this organ ii 

 turf. Versamml. zu Clmr. p. 91 {Nemertes); and dart pointing f irward; which is horny, accord- 

 Rathki, Danzig. Schrift. loc. cit. p. 98 (Bor/asza ing to X)us-ts, and calcareous, according to 6r«ted. 

 striata). This last author has not seen the orifices On each side of this dart, there is a i-eservoir of 

 of the genital organs. Quatrefaffes (Rigne anim. many others, smaller and yet imperfect, destined, 

 illustr. loc. cit. PI. XXXIV. fig. 1, n. n.) did not probably, to replace the former when lost. Dus^es. 

 see them with Nemertes Camilla, and Johnsto7i Johnston, and Quatrefases, who regard this or- 

 is also silent on this subject. According to Orsted gau as an intestinal canal, and Kulliker, wlio con- 

 (Entwurf. &c. loc. cit. p. 25, Taf. III. fig. 47, of siders it preheiisile, all regard these darts as a kind 

 Notospermus flaccidus) the Nemertini secrete of teeth ; but Orsted thinks they serve to excite 

 from the wliolc surface of their body, a gelatinous the genital organs. For my part, they involunta- 

 mucus, which surrounds the eggs, and thus forms rily remind me of the darts of the Ilelicina. 

 an envelope into which they can draw their bodies. [Additional Note.] — I have now satisfied myself 

 Something similar to this occurs with the Lumbri- upon living individuals of 'I'etrastevima, that the 

 cLni and Hirudinei. See below. eggs can escape from the visceral cavity through 



i! The Nemertini being of distinct sexes, this or- numerous lateral openings in the wall of the body, 



gan can be regarded neither as a penis, nor as an I am also satisfied that witli the Nemertini, the 



everted spermatic vessel, as Huschke hits done walls of the digestive canal (the middle body-oavity 



(Isis, 1830, p. 682, Taf. \ [I. fig. 5). More jirop- according to Qiiatrefa^esy are not the ))oints of 



crly could it be considered, with Orsted (Entwurf. departure of the genital organs, as Quatrefases 



&c. p. 25), as an excitatory organ-, although Rathki thinks, aud who also would regard as a digestive 



(Danzig. Schrift. loc. cit. p. 100, and Nov. Act. Acad, tube the snout of these animals, an organ which is 



Nat. Cur. X.X. j). 233)- regards it as of a tactile, yet enigmatical. The very detailed figures which 



and KbUiker of a prehensile naiiu'e (Verhandl. d. this naturalist has given (loc. cit.) of the walls of 



schweiz. p. 90). Other observers agree with the digestive canal of tliese animals, present nothing 



Ehrenbers^ (Symb. phys. loc. cit.) tliat it is an in- like an ovary, and show no ti-ace of tlie presence 



testiue and an everted oesophagus, its orifice being of germs. 

 a mouth ; but this is undoubtedly erroneous. Witii 



