256 



THE CEPHALOPnORA. 



^ 225. 



organs. 



These are cither combined in one individual, or the sexes are sep- 

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

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

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

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

 is continuous with the vagina, there is a Receptaculiim sevnnis. The male 

 nital organs consist of a testicle, a Vas deferens^ and a Ductus ejaculatO' 



<'ii 



rius which opens into a retractile penis. "With the hermaphroditic species, 

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

 testicle with the ovary, and the 1^/5 deferens with the Tula Fallopii ; very 

 often also the vagina is united with the Ductus ejaculatm-ius, forming a 

 cloaca into which open several particular secreting organs. These difi'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 

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

 >[uite 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, Ei-lauterungstafeln lift. V. Taf. 11. 

 fnR. 4, ai. (Liniax), and in Muller^s Arch. 1S35, p. 

 491, Taf. XII. tig. 2 {Helix pomatia) ; Wagner, 

 in IViegmann's Arch. 1S35, I. p. 36S, and Pro- 

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

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

 fig. 7 {Actaeon). 



'i fVasner 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 long body to which is abruptly at- 

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

 with ye.rmetus gigas and triqueter. Those of 

 Trochus also have this form, according to Kiilli- 

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

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

 and taper at both extremities with Turbo, Bncci- 

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

 fig. 5), and Sagitta {Krohn, loc. cit. p. 10, tig. 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 {Kolli- 

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

 mann, loc. cit. p. 52, Taf. III. tig. 8, 9, and my 

 observations in Muller''s Arcli. 1836, p. 240, Taf. 

 X.). With the ])ulmonate Gastero])oda, the sperm- 

 atic particles have only a short incrassated extrem- 

 ity of a spiral form ; see my observations loc. cit. 

 18.36, p. 45, Taf. II. ; Paasch, in JViegmann's 

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

 scrv. an Microscope, Atlas, PI. III. 



The development of these spermatic particles 

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

 which are formed cithers (Daughter-cells) which are 

 changed into the spermatic jnii tides. Hut the cell- 

 membrane of the mother-cell, disappears quite 



* [§ 225, note 2.] My own observatio;iS on the 

 spermatic particles of the Cephalophora and their 



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 Kiilliker, Nordmann, 

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

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

 the more recent researches of Kiilliker, in the Neue 

 Denkschrift. d. allgcm. schwcb.er. Gesellsch. f. d. 

 gesammt. Naturwissensch. 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 

 remarkalile fact ; see my observations in Aliiller'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 livelj' motions. These 

 have been described by Ehrenberg (Symbol, 

 physic. Anim. evertebrat. Dec. I. Phytozua ento- 

 zoa, Appendix) as parasites under the name Pha- 

 cclura 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 

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

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

 of the same kind of spermatic particle : the second 

 he regards as elongated mother-cells containing 

 many ordinary spermatic particles. 



For my part, I do not know how to explain this 

 fact, and I would willingly place the second form 

 in the category of Spermatophora ; but against this 

 opinion, as against that of Kiilliker, and Paasch, 

 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 forms are simultiineously 

 developed in the testicle.* 



development, correspond closely with the above 

 account. Their development in special cells I have 



