230 
Proceedings of Royal Society of Edinburgh. [may 16 , 
5. Researches on the Problematical Organs of the Inverte- 
brata — especially those of the Cephalopoda, Gastero- 
poda, Lamellibranchiata, Crustacea, Insecta, and 
Oligochaeta. By Dr A. B. Griffiths, F.B.S. (Edin.), 
F.C.S. (Lond. & Paris), Principal, and Lecturer on 
Chemistry and Biology, School of Science, Lincoln ; 
late Lecturer on Chemistry, Technical School, 
Manchester, &c. 
Being convinced that a thorough examination (both from a 
chemical and physiological point of view) of the various problem- 
atical organs of the Invertebrata will throw much light on their 
physiology and their relationship to the Yertebrata, these investiga- 
tions have been undertaken with that object in view. 
I have already shown that the so-called " liver ” of Sepia 
officinalis is a true pancreas , and not a liver ( Proc . Roy. Soc. 
Edin., vol. xiii. No. 119, p. 120). 
A. (I.) Nephridium of Cephalopoda. 
Taking a fresh Sepia oficinalis as a type of the Cephalopoda, it 
was found that its nephridia are true kidneys, or renal organs. 
The venous blood, as it passes from the vena cava, is distributed by 
a number of afferent branchial vessels which communicate with the 
sacculated and glandular chambers (the nephridia). The blood 
passes to the gills and then back to the heart. 
After dissecting the nephridia from the bodies of several fresh 
cuttle-fishes, the secretion of these glands was found to be acid to 
litmus paper, the liquid deposits, upon standing a short time, 
earthy matters. These earthy deposits were submitted to chemical 
analysis. They are insoluble in distilled water, but readily soluble 
in acetic acid. On neutralising a portion of the acetic acid solution 
with ammonium hydrate, and then adding ammonium oxalate, a 
white precipitate was obtained, indicating the presence of calcium. 
Another portion of the acetic acid solution was neutralised, and to 
the neutral solution silver nitrate added : a yellowish precipitate 
was obtained. To another portion of the solution, ammonium 
hydrate was added until alkaline, and to this alkaline solution a 
