450 ZOOLOGY. 



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 sev- 

 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 (Gyinnotus eledricus 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- 

 peidce), 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 ale wife, 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, 

 JSrevoortia 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 $9,000,000 annually, whilst those 

 of Great Britain amount to about $8,000,000, and those of 

 Norway about $14,000,000. 



The herring is a deep-water fish which visits the coast in 



