234 Proceedings of Royal Society of Edinburgh, [may 16 , 
nephridia of the Cephalopod, yields uric acid, but no guanin, urea, 
or calcium phosphate. Therefore the “ segmental organs ” of 
Lumbricus are renal in function, getting rid of the nitrogenous 
waste matters contained in the blood, in the perivisceral cavity. 
The largest amount of uric acid was found in the secretion con- 
tained in the muscular part of the “ segmental organ ” (fig. 2, 
outer looj) of nephridium). 
The next table is a summary of the constituents of the nephridia 
of certain divisions of the Invertebrata. 
(Y.) Renal Organs and their Constituents. 
Cephalopoda. 
Gasteropoda. 
Lamellibranchiata. 
Crustacea. 
Insecta. 
Oligochseta. 
Uric acid, 
present. 
present. 
present. 
present. 
present. 
present. 
Urea, 
absent. 
... 
present. 
absent. 
absent. 
Guanin, 
absent. 
absent. 
present. 
absent. 
Calcium phosphate, 
present. 
present. 
absent. 
absent. 
B. (I.) Salivary Glands of Gasteropoda and Insecta. 
The secretions of the “ salivary glands ” of the Insecta (Orthop- 
tera) were investigated by taking as an example the Periplaneta 
orientalis (cockroach). 
The salivary glands of Periplaneta are situated on each side of 
the oesophagus and crop, and extend posteriorly as far as the 
abdomen. They are about u of an inch in length, and composed 
of acini (fig. 3, b). Accompanying the glands are two salivary 
receptacles, one on either side of the crop. A quantity of the 
secretion was extracted by crushing about sixty glands of freshly 
killed cockroaches. It was alkaline to test-papers. A portion of 
the secretion was added to a small quantity of starch, the starch 
being converted into glucose sugar in 12 minutes. The presence of 
sugar was proved by the formation of red cuprous oxide by the 
action of Fehling’s solution. 
Another portion of the secretion was distilled (with the utmost 
care) with dilute sulphuric acid ; and to the distillate ferric chloride 
added, which gave a red colour indicating the presence of sulplio- 
