82 HERBERT E. DURHAM. 
Asteroide Asterias rubens (young and adult). 
os glacialis. 
Cribrella ocellata (vel sanguinolenta). 
Solaster papposus. 
Asterina gibbosa. 
Ophiuride Ophioglypha lacertosa. 
Ophiocoma rosacea. 
Echinoide Echinus sphera. 
Spatangus purpureus. 
Amphidotus cordatus. 
Insecta Dytiscus marginalis. 
Mollusca Unio and Anodonta, sp. 
I. On tHe Fate or InsotusLtE Forricn PARTICLEs. 
In the ‘ Proceedings of the Royal Society’ (26) I have already 
shown that insoluble granules introduced into the body-cavity 
of the common starfish (Asterias rubens) are ingested by 
leucocytes ; and that these particle-holding leucocytes become 
first adherent to the ccelomic epithelium of the dermal bran- 
chi, and then by their own amceboid power make their way 
through the wall of the branchia to the exterior ; arrived at 
the exterior these leucocytes disintegrate. If the migration is 
going on actively, small clumps of colour visible to the naked 
eye may be formed at the summits of the branchize; such 
clumps consist of granule-holding leucocytes on their outward 
journey. 
The same result was obtained when the experiments were 
repeated in the spring of 1888. 
It seemed of interest to see what became of insoluble par- 
ticles introduced into other animals; for though it is well 
known that such material is ingested by ameeboid cells, yet the 
subsequent fate of these pigment-containing corpuscles has not 
been traced in many instances. 
The only animal I have so far experimented with has been 
Dytiscus marginalis; one set of experiments was made 
with Indian ink rubbed from the solid stick in normal physio- 
logical salt solution (sodic chloride, ‘75 per cent.). (Another set 
