XX 
First Report on Economic Zoology. 
Protozoa .... 
Porifera 
Coelentera .... 
Echinoderma 
Platyhelmia . 
Nemertina.... 
Nematoda .... 
Chtetopoda.... 
Crustacea .... 
Arachnida 
Chilopoda .... 
Diplopoda .... 
Hexapoda .... 
Mollusca 
Tunicata 
Pish 
Amphibia 
Reptilia .. 
Birds 
Mammals 
Survey of Group C. 
None. 
None. 
None. 
None. 
None. 
None. 
Various eel-worms ( Anguillulidae ) hasten decay in plants. 
The earthworms form surface soil and bury stones on 
the surface, and prepare seed beds, etc., for plants. 
None. 
None. 
None. 
None. 
Many insects act as scavengers in all parts of the world ; 
the larvae of flies ( Calliphora ) feed upon and hasten 
decay of carrion ; some carrion beetles {Silphidae ) ; dung 
beetles ( Copridae and Dynasticlae) ; burying beetles 
{Nccrophorus') also act as scavengers; humble bees 
( Bombi ) fertilise clover, and many other insects act as 
fertilisers ( Trigona and Vanilla, Blastophaga and figs). 
None. 
None. 
Fish, especially carp, keep water free from insects and decay- 
ing matter, and are used for such purposes in reservoirs. 
None. 
None. 
Vultures, by destroying the flesh of dead animals and man. 
Rats feed upon carrion, as well as sound food ; and also 
jackals and semi-wild dogs. 
GEO UP D. 
Animals which concern Man as causing bodily injury, some- 
times death, to him, and in other cases disease, often of a 
deadly character. 
This large group contains representatives in most of the divisions of 
the animal kingdom. It may conveniently be divided into two sub- 
groups, viz., (a) animals which cause injury, by direct attack, to man, 
and (Jj ) animals which cause disease by acting as germ carriers. 
In the former section parasitism plays an important role. 
Survey of Sub-group ( a ) of Group D. 
ANIMALS WHICH CAUSE INJURY, BY DIRECT ATTACK, TO MAN. 
Protozoa Malarial hoemamcebidre, coccidia, Amccba coli, and 
Trypanosoma in the blood. 
Porifera None. 
Coelentera Jelly-fish, by stinging man when in sea water. 
Echinoderma Spines of Echinus may penetrate the skin. 
Platyhelmia Numerous tapeworms ( Gcstocla ) are parasitic in the 
intestines of man ( Taenia solium, Taenia saqinata), 
and in their cystic or hydatid stage in the various 
organs and connective tissue ( Echinococcus hominis ). 
Flukes ( Trcmatoda ) also occur as parasites in man 
(Bilharzia haematobium , Distomum hcpaticum). 
