HABITS OF THE HERRING AND SHAD. 447 
high degree of elaboration and diversity in the bones of the 
head. The skeleton is usually completely ossified. The 
bones of the skull and of the jaws are fully developed. The 
lower jaw is attached to the skull by a suspensorium of sey- 
eral well-marked bones, including a symplectic, while the 
hyoid and gill arches are well developed, as is the scapular 
arch. The brain has small olfactory lobes and a small cere- 
bellum. The scales are generally present, and either cte- 
noid (i.e., rough-edged) or cycloid (i.e., rounded but smooth 
on the edge). The common examples are the carp, herring, 
trout and salmon, pike, perch, cod, and flounder. 
Turning now to some of the more characteristic members 
of the order, we first notice one of the lowest Teleosts, the 
electrical eel (Gymnotus electricus Linn.) of South Amer- 
ica, which is two metres in length, and is characterized by 
its greatly developed electrical batteries. These are four in 
number, situated two on each side of the body, and together 
form nearly the whole lower half of the trunk. The plates 
of the cells are vertical instead of horizontal, as in the tor- 
pedo, while the entire batteries or cells are horizontal, in- 
stead of vertical, as in the electrical ray. The nerves sent 
to the batteries of the eel are supplied by the ventral 
branches of about two hundred pairs of spinal nerves. 
Succeeding these and allied forms are the herrings (Clu- 
peide), represented by the common English herring, Clupea 
harengus Linn., which inhabits both sides of the North 
Atlantic, extending on the American side from the polar 
regions to Cape Cod; the alewife, Pomolobus pseudoharengus 
Gill, which ranges from Newfoundland to Florida ; the shad, 
Alosa sapidissima Storer, which has the same geographical 
distribution as the alewife; and the menhaden or pogy, 
Brevoortia tyrannus Goode, which extends from the coast 
of Maine to Cape Hatteras. These, with the cod, hake, 
‘haddock, salmon, and a few other species, comprise our 
most valuable marine food-fishes. The fisheries of the 
United States yield about $40,000,000 annually, whilst those 
of Great Britain amount to about $40,000,000, and those of 
Norway about $10,000,000. 
The herring is a deep-water fish which visits the coast in 
