108 
numerous ip their produce. The squalus squatinus, 
however, or angel fish, probably so called, says 
Stewart, from its deformity, brings forth thirteen 
young. Probably most of the oviparous, as those 
of the genus raia, to which the torpedo, skate, and 
thornback belong; and those of the genus squalus, 
the sharks and the dog-fish, which produce their 
full-formed young in horny square bags or sheaths, 
with long-twisted strings, or bristles at the corners, 
have a proportionally small progeny, compared with 
most other fish. The roe of a herring is said to 
produce 10,000 ova. Stewart says of the bream, 
Cyprinus brama, that it deposits in May about 
137,000 ova. Of the rays, Stewart says, they are 
not very fertile, and produce but one young at a 
time. Lewenhock found in the roe of a sturgeon 
many thousand millions. 
The progeny of most insects is very numerous ; 
but the apparent paucity of some species demon- 
strates a great diversity in this respect. For ex- 
ample : a common wasps’ nest is said by Mr. Kirby, 
vol. I. p. 501. to contain about 16,000 cells: that of 
the vespa holsatica about thirty. The vespa_pa- 
rietum attaches its small group of about twenty in- 
verted crucible-like cells to a piece of wood without 
any covering. Humble bees are said to vary in 
their numbers, rarely exceeding’ 300; often not 
more than twenty. The apis muraria forms with 
fine sand, agglutinated by her own saliva, an assem- 
blage of cells, rarely exceeding eight in number, 
depositing an egg in each, with a store of honey for 
