256 



THE CEPHALOPHORA. 



«^225. 



organs. Tliese are either combined in one individual, or the sexes are sep- 

 arate. In most species there are copuhitory organs. The genital organs 

 have several uneven divisions, which, when fully developed, are arranged 

 as follows : A Tuba Fallopii passes from the ovary into the uterine sao, at 

 whose base is an organ which secretes albumen, while at the point where it 

 is continuous with the vagina, there is a Receptacuhim semi/iis. The male 

 genital organs consist of a testicle, a Vas defere7is, and a Ductus ejaculato- 

 rius which opens into a retractile penis. With the hermav»hroditic species, 

 these two kinds of genital organs are more or less blended together, — the 

 testicle with the ovary, and the Vas deferens with the Tuba Fallopii ; very 

 often also the vagina is united with the Ductus ejaculatorius, forming a 

 cloaca into which open several particular secreting organs. These difl'er- 

 ent male and female organs are usually lined internally with ciliated 

 epithelium. 



The eggs of these animals have, at their escape from the ovary, a round 

 and sometimes an elliptical form, and are composed of a thin chorion en- 

 closing a finely-granular vitellus of variable color, which contains a, 

 germinative vesicle and dot.'^' The sperm is white and opalescent, and 

 quite crowded with very active spermatic particles. These last are either 

 of the form of Cercaria, or consist of a very long filiform body, one extrem- 

 ity of which is incrassated and often of a spiral form. The trembling,^ 

 undulatory movements of these particles cease when placed in water, with 

 those species which have copulatory organs ; they become twisted into loop- 

 like forms and are finally rigid and motionless.'^' 



1 See Cams, Erläuterungstafeln Hft. V. Taf. II. 

 fig. 4, ai. {Limax), aurt in Muller^s Arch. 1835, p. 

 491, Taf. XII. fig. 2 (He/ix pomatia) ; Warner, 

 in tViegmann's Arch. 1835, I. p. 368, and Pro- 

 dromus, loc. cit. p. 7, Tab. I. fig. 6, 7 {Helix and 

 Buccinum) ; and AUman, loc. cit. p. 152, PI. VII. 

 fig. V (Actaeon). 



'■i Wagner and Erdl (Froriep^s neue Notiz. No. 

 249, p. 98) have found with Chiton, Patella, and 

 Haliotis, spermatic particles of a Cercarian-form, 

 that is with a lung body to wliich is abruptly at- 

 tached a hair-like tail. I have seen a similar form 

 with Fermetus gigas and triqaeter. Those of 

 Trochus also have this form, according to Kolli- 

 ker (Beitr. loc. cit. p. 28), but the middle of their 

 body has a slight constriction. They are hair-liUe, 

 and taper at both extremities with Turbo, Bucci- 

 num, Purpura {KölUker, loc. cit. p. 25, Taf. I. 

 fig. 5), and Sagitta {Krohn, loc. cit. p. 10, fig. 12). 

 With other marine Gasteropoda, as for example, 

 Carinaria, these particles are hair-like, but with 

 one of their extremities slightly incrassated {Milne 

 Edwards, Ann. d. Sc. Nat. XVIII. p. 324, PI. XI. 

 fig. 7) ; and with Doris, Tergipes, and Paludina, 

 this thickened extremity has a spiral form {KölU- 

 ker, JJeitr. loc. cit. p. 35, Taf. I. fig. 6 ; ßlord- 

 mann, \o<:. cit. p. 52, Taf. III. fig. 8, 9, and my 

 observations in ßhäler^s Arch. 1836, p. 24Ü, Taf. 

 X.). With the j)ulmonate Gasteropoda, the sjierm- 

 atio particles have oidy a short incrassated extrem- 

 ity of a sjiiral form ; see my oliservations loc. cit. 

 1836, p. 45, Taf. II.; Paasch, in fViegrnann's 

 Arch. 1843, I. p. 71, Taf. V., and Dujardin, Ob- 

 serv. au Microscope, Atlas, PI. III. 



The develoimient of these sjjermatic particles 

 takes place in two large cells (Mother-cells), in 

 which are formed others (Daughter-cells) which are 

 changed into the spermatic iiarticles. IJut the cell- 

 membrane of the mother-cell, disap])ears ijuily 



* [§ 225, note 2.] My own observations on the development, correspond closely with the above 

 spermatic particles of the Cephalophora and their account. Theij da 'sJopment in special c? 'Js I have 



early and its contents are condensed into a solid nu- 

 cleus around which are grouped the daughter-cells, 

 ultimately forming a bundle of spermatozoa. See, 

 beside these observations of Kölliker, Nordmann > 

 and Paasch, loc. cit., those of H. Meckel, in Mul- 

 ler's Arch. 1844, p. 483, Taf. XIV. fig. 9-13, and 

 the more recent researches of Kölliker, in the Neue 

 Denkschrift, d. allgem. schweizer. Gesellsch. f. d. 

 gesammt. Natur wissensch. VIII. 1846, p. 4, Taf. 

 I. fig. 1-10 {Helix pomatia). 



The presence of two kinds of spermatic parti- 

 cles in the sperm of Paludina vivipara, is a very 

 remarkable fact ; see my observations in Mailer's 

 Arch. 1836, p. 245^ Taf. X. 



Beside the hair-like spermatic particles already 

 mentioned, there are long cylindrical bodies, from 

 one of the extremities of which project many deli- 

 cate filaments having very lively motions. These 

 have been descril)ed by Ehrenberg (Symbol, 

 physic. Anim. evertebrat. Dec. I. Phytozoa euto- 

 zoa, Appendix) as parasites under the name Pha- 

 celiira paludinae. 



Paasch {Wiegmann's Arch. 1843, p. 99, Taf. 

 V. fig. 8), on the other hand, regards them as bun- 

 dles of spermatic particles of the normal form, and 

 Kölliker (Beitr. loc. cit. p. 63, and Neue Denkschr. 

 loc. cit. p. 41) considers them only as two forms 

 of the same kind of s|)crmatic particle : the second 

 he regards as elongated mother-cells containing- 

 many ordinary spermatic iiarticles. 



For my part, 1 do not know how to explain thi» 

 fact, and I would willingly jjlace the second form 

 in the category of Si)ermatophora ; but against this 

 opinion, as against that of Kölliker, and Paaschy 

 it can be urged that, with the second form, the ex- 

 tremities are never thickened or spiral, as is true 

 of the first, and that both forma are simultaneously 

 developed in the testicle.* 



