636 
NATURAL HISTORY. 
one, and another flat, as if split in two, but both very bright 
and lustrous. 
The fresh-water streams contain innumerable diminutive 
shells, the largest is a Melanopsis , which is met with in fresh- 
water streams, and also near the mouth of rivers. A minute 
shell (Animalcula Trichotropis) is found in every rivulet ; 
when full-grown the whorls are encircled with spines, when 
young it is without them ; this is the chief food of the inanga, 
which swallows them entire, and thus renders the Taupo 
inanga inferior to those of other lakes, because they remain 
undigested, and render it gritty in eating. 
The rocky streams have a little ancylus, and amongst other 
caddis worms, one kind of Phryganea, which inhabits a 
dentalia-shaped horny case, which might almost be termed 
a shell, and another which forms its case of agglutinated 
particles of sand in the form of a trochus, and it was a ques- 
tion with Mr. Swainson, whether it was a caddis worm or not. 
In the salt swamps is found a shell of fam. auriculidce, and 
a solitary pupa may be met with in the woods. 
The Physa variabilis inhabits fresh-water lakes near the 
sea, as also a limnea, with the opening on the left side. 
The fam. Octopodidoea is well represented, and if the 
accounts of the natives can be relied upon, they attain a 
very large size, and it required no ordinary stock of courage 
to encounter them. 
The Sepia is called by the natives he wehi; it is very 
abundant in all the New Zealand seas. The Loligo is more 
rarely met with ; to one of these belongs the beautiful little 
chambered spirula so common on our shores, and so closely 
resembling the nautilus. 
Several species of the Echinus (heMna) are found on all the 
shores of New Zealand. Some attain a very large size, are 
eaten alive, and esteemed peculiarly good. It is recorded 
that they formed the chief dish of the famous supper of 
Lucullus, when he was made flamen martialis, priest of Mars. 
A large flat kind is very common, both in a living and fossil 
state, but the great round one is not met with as a fossil. 
In the Wellington Harbour a very fragile echinus is dredged 
