119 
seen, especially the larger, with their heads opposed 
to the current, watching in stillness for their casual 
prey. Gudgeons and minnows are always in shoals. 
Of marine fish many of the most voracious prey by 
night and live solitary, swimming often at the 
bottom ; others seek their food by day, and wander 
in troops from sea to sea, as the herring and the 
cod, swimming near the surface. 
Serpents, even where most numerous, exhibit ge- 
nerally anti-social habits; yet great numbers of the 
anguis fragilis are said to have been found frozen 
together in winter. The lacerta iguana is solitary : 
the species agilis, on the walls of France and Italy, 
is numberless. Toads are lonely; frogs notoriously 
social. Turtles congregate. Land tortoises are for 
the most part solitary, even in their hybernation. 
Birds of prey, especially the nocturnal, are unso- 
cial. Granivorous birds flock together, especially in 
winter. The carrion crow is a bird of solitude: the 
rook, of even apparently organized society: many 
which separate in pairing time congregate in winter. 
The swallow tribes seem to become more and more 
associated as their season for migration approaches. 
The common wren, motacilla troglodytes, is a noto- 
rious little anchorite. The fringilla domestica, or 
house-sparrow, is quite opposite in its habits during 
all seasons. The bulfinch is commonly lonely, or 
only seen in pairs. Linnets are usually found in 
flocks '. . 
Beasts, as well as birds of prey, for the most part 
i See White’s Selborne, &c. 
I 4 
