CTENOPHORA 



inent was found by Chun; Ctenoph. d. Golfes v. Neapel. Taf. XVI, Fig. 481. The ripe spermatozoa 

 are found in the upper part of the testis. They break through the entodermal lining into the genital 

 cavity, where they may be found in large quantities in the sections (PL VII, Fig. 9). The peculiar fact 

 observed by Chun (Dissogonie p. 98, Taf. XIII, Fig. 2, 6) that in Bolina "die Schwanze der Sperma- 

 tozoen zu keilformig gestalteten Biindeln vereint sind, welche allmahlich sich zwischen das Gefass- 

 epithel einzwaiigen und schliesslich nach der Leibeshohle durchbrechen" has not been observed here. 

 I have not found the material suited to working out the minor histological details of the development 

 of the spermatozoa. 



The figures 56, PI. VI, are of value for determining the question about the origin of the 

 genital cells in Tjalfiella. It is seen there, especially very distinctly in fig. 5, that the germinal 

 zone is a direct continuation of the low entodermal epithelium lining the lower wall of the genital 

 cavity. It appears that on the limit between this low epithelium and the higher epithelium which 

 covers the genital organ a constant proliferation of the cells takes place, most of the young cells being 

 added to the germinal layer. It can scarcely be denied that all evidence is in favour of the entodermal 

 origin of the genital cells in Tjalfiella. This case is thus quite in accordance with the view main- 

 tained by Chun that the genital cells of the Ctenophores are of entodermal origin, which view is 

 also supported by the researches of Gar be 1 ). The opinion of Hertwig (Op. cit.) later on maintained 

 anew by Samassa 2 ) that they are of ectodermal origin seems to me definitely refuted by Chun; the 

 ectodermal invaginations of Callinira bialata which have caused this opinion appear to be a kind of 

 sense organs peculiar to this species and have not been found in any other Ctenophore as yet. - 

 It may be worth recalling here the series of glands which occur along the subventral ribs in 

 Eurhauiphcea vexilligera Gegenb. and which secrete a red fluid, when the animal is touched. (Comp. 

 Const. N. Jonescu: Uber die Ctenophore Eurhamphaea vexilligera. Jen. Zeitschr. f. Naturwiss. 

 Bd. 43. 1908. p. 685691. Taf. XXIV). The structure of these glands being as yet unknown, it is, of 

 course, impossible to say anything definitely about their homologies. But it might perhaps not be 

 unreasonable to suggest that they could have some relation to the ectodermal sacs of Callianira. 

 That Chttn (Ctenoph. Golfes v. Neapel, p. 296) is inclined to suppose a genetic relation between 

 EurhamphfEa and Callianira is also worth mentioning in this connection. Though Jonescu denies 

 the existence of any nearer relation between these two forms, the suggestion of Chun certainly 

 deserves a more careful investigation. 



More recently a third view of the origin of the genital cells of the Cteuophores has been 

 maintained by Karl Cam. Schneiders), viz. that they are of mesodermal origin. It does not appear 

 to me that the reasons produced by Schneider for this opinion are very convincing, as also 

 B. Hatschek (Uas neue Zoologische System, 1911. p. 13) finds them "noch nicht beweiskraftig" ; being, 

 however, not profoundly acquainted with histology, I do not venture on a detailed criticism of his state- 

 ment. I would only point to some facts, which appear to me very unfavourable to his theory of the meso- 



') Aug. Garbe. Untersuchungen fiber die Entstehung der Geschlechtsorgane bei den Cteuophoren. Zeitschr. f. wiss. 

 Zool. Bd. 69. 1901. p. 472491. Taf. XXXVI XXXVII. 



a ) P. Samassa. Uber die Entstehung der Genitalzellen bei den Ctenophoren. Verhandl. d. naturh. -medic. Vereins zu 

 Heidelberg. N. F. Bd. V. 1893. (This paper has not been available to the author). 



3) Karl Camillo Schneider. Histologische Mitteiltmgen. 1. Die Urgenitalzellen der Ctenophoren. Zeitschr. f. wiss. 

 Zool. LXXVI. 1904. p. 388 399. Taf. XXIV. 



