620 DR. R. V. ERLANGER. 
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XXI—Xxv. 
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und Gasteropoda,” Theil ii, ‘ Mittheilungen aus du Zool. Stat. zu 
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Additional Note.—I have lately examined Trochus and 
Turbo, in order to test v. Jhering’s and B. Haller’s state- 
ments about the existence of a proper genital duct (loc. cit.). 
V. Jhering’s figure is absolutely schematic, and is not 
accompanied by a detailed description. As he failed to recog- 
nise the existence of the left kidney, it is highly probable that 
he mistook one or the other renal duct for the genital duct. 
Haller simply mistook the right renal duct for a proper 
genital duct, having stated that the right kidney opened into 
the left one. . 
I was unable to find any proper genital duct in Trochus 
turbinatus and Turbo rugosus, although I used both the 
method of dissection and that of unbroken series of sections. 
On the other hand, the appearance, position, and the 
vicinity of the genital gland to the glandular portion of the 
right kidney and the beginning of the right renal duct are 
the same as in Haliotis. I am therefore led to the con- 
clusion that the sexual products are expelled by the right 
kidney. . 
Should this conclusion be correct (an absolute proof can 
only be given by finding ova or sperma in the right renal 
duct), all primitive Prosobranchs would be devoid of a proper 
genital duct, the right renal duct serving also as a genital 
