THE RENAL OUGANS (nEPHKIDIa) OF PATELLA. 369 



The Renal Organs (Nephridia) of Patella. 



J. T. Cunningliam, 



Fellow of University College, Oxford. 



The existence of two renal organs in Patella was first 

 pointed out by Professor Lankester in 1867,^ and he stated at 

 the same time that he believed he had discovered, by careful 

 dissection, a minute orifice leading from the pericardium into 

 the left and smaller of the two. In 1877 Von Jhering, in a 

 ])aper on the " Morphology of MoUuscan Kidneys/'^ con- 

 firmed the account given by Professor Lankester, at the same 

 time empliasising the fact that the two renal sacs are dis- 

 tinct, as had already been stated by Lankester, who says, 

 after describing the two renal papillse with their openings to 

 the exterior, "These two orifices represent two renal 

 organs, as in Lamellibranchs." Von Jhering was unable to 

 find any pericardial openings. In April, 1881, Professor Lan- 

 kester and Mr. A. G. Bourne^ examined fresh limpets as to the 

 pericardial orifice of the kidneys. They found that injections 

 from the pericardium passed sometimes into the right and 

 sometimes into the left renal sac, but that there was only one 

 orifice leading into a narrow subanal tract belonging to the 

 organ of the right side. Professor Lankester suggested to me 

 some time ago that I should endeavour to settle definitely this 

 question of the reno-pericardial pore in Patella by cutting a 

 series of sections through the parts, and so tracing their relations 



» 'Ann. and Mag. Nat. Hist.,' 3rd series, vol. 20, 1S67. 



2 • Zur Morph. der Niere der MoUusken Zeitsclir. f. w. Zool.,' Bd xxix. 



3 '• On the originally bilateral character of Renal Organ of Prosobrancbia," 

 • Ann. and Mag. Nat. Hist.,' vol. vii, 18S1. 



