1887.] Dr A. B. Griffiths on Organs of the Invertebrata. 233 
(III.) Renal Organs of the Lamellibranchiata and Crustacea. 
The organ of Bojanus or nephridium of My a arenaria (as well as 
Anodonta cygnea ) contain uric acid and urea in their secretions, 
and there is also a small quantity of calcium phosphate present in 
the secretion of the organ of Bojanus. Mr Follows and myself 
( Chemical Neivs, vol. li. p. 241, and Jour. Cliem. Soc. [Abstracts], 
1885, p. 921) found “ a salt of calcium in minute quantities f hut 
we could not make out the acid in combination ; subsequently it 
was found to he phosphoric acid. The “ green glands ” of Homarus 
vulgaris (lobster) easily yield uric acid crystals and small quanti- 
ties of the base guanin. 
Cuticle. ^ 
Epidermis. ^ 
Circular muscu- 4 
lar layer. 
Longitudinal 4 
muscular layer. 
Outer loop of A 
nephridium. 
External open- 
ing of nephri- 
dium. 
Pig, 2. — Diagram of Nephridium of Lumbricus terrestris. A, the secretion 
of the outer loop of the nephridium (segmental organ) contains the hugest 
quantity of uric acid. 
(IV.) Renal Organs of the Oligochceta. 
After treating the segmental organs (nephridia) of freshly killed 
Lumbricus terrestris (earthworm) in a similar manner to the 
Dorsal vessel. 
Middle loop of 
nephridium. 
Typhosole. 
^ Hepatic cells, so- 
called “ liver.” 
» Inner loop of 
nephridium, 
.> Epithelium of 
intestine. 
Ventral v. 
^ Coelom. 
Internal opening 
of nephridium. 
> Vent, nerve cord. 
Subneural vessel. 
