336 



Free sperms are found in the coiled part of the spermiduct for 

 some distance — in fact up to the point at which the ducts from the 

 mesonephros enter it: from this point onwards spermatophores are 

 present. As the spermatophores are broken down in the posterior 

 region of the spermiduct, it seems probable that the secretion of 

 Leydig's gland consists of a substance which serves to preserve the 

 vitality of the sperms. 



In the enlarged lower end of the spermiduct (vesicula seminalis), 

 which is divided up by transverse partitions, a greenish jelly is found 

 which surrounds the spermatophores and possibly helps to dissolve 

 them: free sperms are found at its posterior end and in the urinogenital 

 sinus. In some rough notes in our possession on a dissection of 

 Callorhynchus, made by the late Professor T. Jeffery Parker in 1891, 

 are some statements which bear out this view. On placing some of 

 the contents of the seminal vesicle in water he found that the jelly 

 was soluble with much frothing, and that the sperms were left free: 

 he also states that jelly containing active sperms was present in the 

 urinogenital sinus. 



We hope to add further details in a subsequent paper, in which 

 we propose to deal with the whole urinogenital apparatus of both 

 sexes, several interesting points in connexion with which (and also 

 with the mesonephros of Plagiostomes) have presented themselves in 

 the course of our investigations. 



February 27th 1909. 



Postscript. Since this paper was written, we have referred to 

 Borcea's important monograph, in which both the anatomy and em- 

 bryology of the parts in question are described in numerous Plagio- 

 stomes ("Recherches sur le Systeme uro-genital des Elasmobranches", 

 Archives de Zool. exp. et gen., Serie 4, Tome 4, 1906). Boecea states 

 that the longitudinal canal of the epididymis is present in most adult 

 Plagiostomes and is in relation with the tubules of this organ; but 

 that "chez les Raies le premier canal segmentaire forme directement le 

 vaisseau efferent, sans transformation prealable en rein et se continue 

 directement avec la partie initiale du canal de Leydig" (p. 343). 



Plagiostomen" etc., Arb. aus dem Zool.-zoot. Inst, in Würzburg, Bd. 2, 

 1875), Rabl remarks: — "Möglicherweise gehen übrigens noch einige 

 Kanälchen des proximalen Endes der Urniere in späteren Stadien beim 

 Männchen zu gründe" ("Ueber die Entwickelung des Urogenitalsystems 

 der Selachier", Morphol. Jahrb., Bd. 24, 1896, p. 746). 



Abgeschlossen am 16. April 1909. 



Frommannsche Bachdrackerei (Hermann Pohle) in Jena. 



