248 Dr. T. Williams on the Mechanism of Aquatic 



Gasteropocls were believed by Meckel* to constitute the true 

 renal system of these animals. A new demonstration of their 

 renal character was subsequently rendered by Jacobsonf by the 

 discovery of uric acid in the substance of these glands. His 

 researches comprised analyses of the glands of Helix pomatia, 

 Limax niger, Lymneiis stagnalis and Planorbis cornea. Jacobsou's 

 views, however^had been anticipated by Dullinger and HolmlicbJ, 

 who had long previously indicated these glands as the real 

 kidneys of these animals. It is stated by Siebold and Stannius§ 

 that in the dried kidneys of Helix pomatia and Paludina vivipara, 

 when treated with nitric acid and ammonia, considerable quan- 

 tities of murexid may be discovered. Treviranus has descended 

 to the minuteness of asserting that in these Gasteropods a por- 

 tion of the pulmonary or branchial, recently arterialized blood 

 passes through the kidneys in its path to the auricle. In another 

 place in their excellent work, Siebold and Stannius observe that 

 in the Pectinibranchs the kidney is replaced by a gland w^iich is 

 situated behind the branchia between the heart and the liver, 

 and which in the marine species secretes the purple liquid. This 

 is the gland which Dr. Sharpey has described as a bipectinate 

 and supplementary gill. 



Kidneys have also been described by Quoy and Gaimard, 

 under the several names of muciparous glands, organ of the 

 purple, depurating organs, &c.y in Phasianella, Turbo, Bucci- 

 nuni, Mitra, Oliva, Capnea, Harpa, Dolium, Cassis, Purpura, 

 Fusus, Auricula\\. Leydig has also given an account of the 

 renal siphon of Paludina Vivipara. JMore recently Mr. Huxley^ 

 has expressed his belief in the correctness of the prevailing views 

 as to the true renal nature of the glands contained in the breath- 

 ing-chamber of the branchiferous and pulmoniferous Gasteropods, 

 and has adopted as conclusive of all doubts, the results obtained 

 by the lithic acid tests in the hands of Jacobson, Meckel and 

 Kolliker**. 



The preceding outline of the literature of the question 

 which relates to the renal system of the Invertebrata will suf- 

 fice to reveal a chaos out of which it does not seem easy to 

 evoke aught that is orderly and consistent. It is evident that 

 the same names have been applied by different observers to very 



* MuUer, Arch. 184(5, p. 13. taf. 1. 

 t MuUer's Arch. vi. 1846. 



X Dissertatio de Ilelice pomatia. Hirceb. 1813, p. 23. 

 § Comparative Anatomy of the Invertebrata, transl. by Burnett, p. 253, 

 note 3. 



II Vovage de I'Astrolabe, Zoologie, ii.; or Isis. 1834, p. 285; 1836, p. 31. 

 H " On the Morphology of the Cephaloiis MoUusca," Phil. Trans. 1853. 

 ** Entwickelungsgeschichte der Cephalopoden. 



