^227. 



THE CEPHALOPHORA. 



261 



Underneath the point of insertion of this vesicle upon the vagina, are 

 various glandular appendages which open into this last or into the genital 

 cloaca. But as jet their function is unknown. With the Pteropoda, and 

 Heterobranchia, there is a single appendage only, consisting of a simple 

 tube.*^^' To this same category belongs, also, the dart-sac, — a very remark- 

 able cylindrical organ opening into the genital cloaca.'^®* Its walls are 

 quite thick, and on each side of its base is a group of more or less numer- 

 ous caeca.'^'^* At the bottom of this sac is a conical papilla which secretes 

 a calcareous concrctiou of the form of a lance-head with the point down- 

 wards, — the Dart. This is projected during copulation, and often remains 

 sticking in the skin near the genital opening. Its loss is subsequently 

 replaced by the secretion of another in the same place. '^'*' 



The male copulatory organs consist of a more or less long, projecting 

 Penis, which, when at rest, is either retracted freely between the other 

 viscera of the cavity of the body, or enveloped wholly or in part in a proper 

 sheath {Praeputium). 



This penis consists, nearly always, of a hollow fleshy cylinder, which is 

 usually closed at its posterior extremity, and has, behind, a long flagelli- 



It is very long with Bulimus radiatus, Helix 

 arhustorum, lactea, and vemiiculata ; very 

 short, on the other hand, with Helix pomatia, 

 nemoralis, and candidis.iima. It is entirely 

 wanting with Helix fruticuin, strigella, and 

 rhodostoma. With Helix ab^ira, it communi- 

 cates directly with the seminal sac (see the figures 

 of Erdl, and Paasch). With Doris, the Recepta- 

 culum seminis has a peculiar structure ; it is 

 kidney-shaped, and from its concavity arises a 

 very large excretory duct, arcuate, and opening 

 into the genital cloaca, which has not only a 

 caecal appendage, but also a short canal that 

 communicates with the base of the uterus (H. 

 Meckel, loo. cit. p. 496, Taf, XV. fig. 2). Further 

 research must determine if the canal which Nord- 

 mann (loc. cit. p. 50, Tab. III. fig. -5, d.) has 

 observed upon the seminal sac of Tergipes with- 

 out being al)le to ti'ace it to its extremity, is a 

 simple deverticulura, or a canal communicating 

 with the female genital organs. 



15 An analogous appendix, of a round form, has 

 been described with Cymbulia, and Limacina, as 

 a prostate by Fan Benedcn (Exerc. zoot. loc. cit. 

 PI. I. fis. 17, e. V. fig. 12, B.), and as a testicle by 

 Eschricht, with Clio (loc. cit. Tab. III. fig. 2.5, 

 26). There is a long glandular appendix upon the 

 genital cloaca with Doridiiim, Pleurobrnnchaea, 

 and Diphyllidia {H. Meckel, loc. cit. Taf. XV.). 

 As yet the function of this gland is only hypotheti- 

 cal. Perhaps it furnishes the viscid substance en- 

 veloping the eggs during their deposition, or it may 

 be a copulatory pouch (Bursa copulatrix). But it 

 is quite probable that the penis enters the peduncle 

 of the Receptaculum se)ninis during copulation, 

 for with most Cephalophora the penis and the 

 peduncle are of the same length. 



It) The dart-sac, which is more or less long, is 

 found with many species of Helix. It is absent 

 with Helix algira, candidissima, cellaria, and 

 verticillus. It is double with Helix ericetorum. 



and with Helix strisella, is replaced by two very 

 long coeca ; see Wolinlicli, Erdl, and Paasch, 

 loc. cit. 



11 Two considerable groups of dichotomously 

 ramified caeca are found with Helix pomatia, 

 adspersa, austriaca, lactea, naticoides, and ver- 

 miculata, while with Helix umbrosa, strigella, 

 and striata, there are only four caeca on each side. 

 With Helix incarnata, and nemoralis, there are 

 three, and two only with Helix lapicida, arbus- 

 toriim, and personata ; see Cuvier, Wohnlich, 

 Erdl, Paasch, loc. cit. and Wagner, loon. zoot. 

 Tab. X\X. fig. 11, 12. As to the use of these 

 glandular tubes, I would suggest the view that 

 they secrete a coagulable substance, which, during 

 the coition, envelops the sperm like a spermato- 

 phore to conduct it into the seminal sac. Indeed, 

 I am much inclined to regard as the debris of a 

 spermatophore the thin horny bodies of a peculiar 

 aspect, which, with Helix hortensis, arbustorum, 

 and nemoralis, often project out of the genital 

 cloaca after fecundation, and which, when they 

 have left it, are rolled in a spiral form at both ex- 

 tremities. When carefully examined they will be 

 found composed of several layers of coagulated 

 albumen, and to be involved in the peduncle of the 

 Recejitaculum seminis ; see Huschke, in Meck- 

 eVs Arch. 1826, p. 629, Taf. VII. fig. 9, and Cams, 

 in Mailer's Arch. 1835, p. 495," Taf, XII. fig. 

 4-7. 



ifi The dart is hollow and of the form of a cylin- 

 drical stylet with Helix ericetorum, and striata ; 

 but with Helix pomatia, hortensis, and adspersa, 

 four, sharp denticulated edges, extending its whole 

 length give it a very elegant form ; see Prevost, 

 in Mem. de Geneve, loc. cit. V. p. 121, PI. I. fig. 

 7, and Cams, in Muller's Arch. 1835, p. 494, Taf. 

 XII. fig. 9, 12. 



It is probably an excitatory organ, for the snails 

 reciprocally jjrick each other before coition.* 



has so well figured. He found its contents to be 

 spermatic particles, but, in regard to its being a 

 seminal receptacle, he remarks : " This, however, 

 cannot be considered wholly as its use ; for it 

 secretes a mucoid matter which may probably 

 facilitate the passage of the ova thi-ough the vagina 

 and cloaca," p. 234. — Ed. 



* [§ 227, note 18.] For the relations of the dart- 

 sac with the American Helices, see Leidy, loc. cit. 

 He adds, " The dart-sac and multifid vesicles, so 

 common in European species, are very rare in 

 American species." The dart-sac has been found 

 in only foui- species. — Ed. 



I 



