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THE BLUE SHARK. 
A specimen of the other genus, Centrocymnns , was taken near Gloucester, Massachusetts. 
Its range extends to Portugal, on the opposite shores of the Atlantic. 
The Nurse Shark family includes two genera and four species. These Sharks are not at 
all the same as the so-called Nurse of the fishermen of the Northern States. It is a large, 
small-mouthed, harmless Shark, seen in shoals in the warm waters of the sub-tropical and 
tropical regions. We have seen shoals of this Shark, numbering scores, feeding in the shal- 
low lagoons of the Tortugas reef. Their mouths are situated beneath the snout, as is the case 
with most Sharks ; but in this species they are somewhat like those of the sturgeons, and are 
not armed with teeth of any considerable size ; consequently, their prey consists of small stuff, 
as the mollusca and Crustacea of the shoals. The wide-spread lagoons on the reef at Tortugas 
are rich feeding-grounds for this Shark. Its rather clumsy form and sluggish, harmless 
habits render it a tempting source of sport for the youngsters resident there. To sail with 
a fair wind into a drove of a hundred, more or less, and harpoon a sizeable one that would tow 
the boat over the reef to their hearts’ content, was a privilege our boys highly appreciated, 
though, perhaps, savoring of the ruder class of sport. 
The length of this species is from six to ten feet. Those we were accustomed to see were 
about seven feet on an average. 
Several times we found the young of this species ensconced in some crevice of the broken 
coral rocks. 
Under the family designated as “True Sharks” are embraced twenty or more genera, and 
about sixty species, found in all seas. 
The Smooth Hound, or Dog Stiapk ( Mustelus hinnulus). This is the smallest of the 
Sharks of the American waters, and is identical with that of Venice. Another of this genus 
frequents the coast of California. In the same waters a kind nearly allied is 
The Common Dog Shark ( Triads semifasciatus). It is distinguished by a row of 
rounded black spots along the sides of the body, alternating with the interdorsal cross bars. 
Another, called T. henlei , inhabits the same waters. 
The Tiger Shark ( Galeocerdo tigrinus) is the sole representative of this genus in 
America, being found in waters near Cape Cod. It also inhabits the Indian Ocean. It is 
rather large, and peculiar for the variegated appearance of coloration. 
Another genus, embracing species called Smooth-toothed Sharks, is represented in Amer- 
ican waters by the Smooth -toothed Shark ( Aprionodon punctatus). 
Oblique-toothed Shark (8 coliodon tei'rce-novce ), called also Sharp -nose, is found from 
Newfoundland to South America. Rather small in size. 
The family of Hammer-heads embraces three genera and five species, which inhabit most 
seas. They are large Sharks, known at once by their most singularly-shaped heads. 
Shovel-head, or Bonnet-head {Heniceps tibur ), inhabits the Atlantic southward, and 
extends to China. 
Under the term Sharp-nosed Sharks are enumerated several large species, that live in 
tropical seas, of which there is one species in our waters. 
The Spotted-fin Shark ( [sogompliodon limb aim). A stray specimen was found at 
Wood’s Hill, Massachusetts. 
The Blue Shark, so called from the fine slaty-blue color of its skin, is a not unfrequent 
visitor of the shores of Northern Europe, and is the object of the deadliest hatred to the 
fishermen, who are sometimes doomed to see their fish stolen, their nets cut to pieces, 
and their lines hopelessly ruined by this fish, without the least power of checking its 
depredations. 
About the month of June, according to Mr. Couch’s observations, this Shark makes its 
appearance on the coasts, and has sometimes been so plentiful that nine or ten have been 
taken by the fishing boats in a single day. As the fishermen are hauling up their lines with 
the fish upon the hooks, the Blue Shark will follow the fish as it is drawn upwards, seize 
upon it, and hook itself for its trouble. Exasperated by the unsuspected check upon its 
