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342 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [54} 
Captain Scammon, in his ‘ Marine Mammals”, gives the following 
confirmation of Captain Atwood’s views, speaking of the habits of the 
hump-back whale of the Pacific: 
‘In their wanderings they are addicted more than any other roqual 
to ‘breaching’, ‘bolting’, and ‘finning’. In the mating season they are 
noted for their amorous antics. Atsuch times their caressings areof the 
most amusing and novel character, and these performances have doubt 
less given rise to the fabulous tales of the Sword-fish and thrasher at- 
tacking whales. When lying by the side of each other the Megapteras 
frequently administer alternate blows with their long fins, whichelove- 
pats may, on a still day, be heard at a distance of miles. They also rub 
each other with these same huge and flexible arms, rolling occasionally 
from side to side, and indulging in other gambols which can easier be 
imagined than described.” 
43.—ENEMIES. 
Such a large animal as the Sword-fish can have but few antagonists. 
whose attacks would be disastrous. The tunny or horse-mackerel, 
Orcynus thynnus, other Sword-fishes, and sharks are its only peers in 
size, and of these the sharks are probably its worst foes. 
Capt. N. E. Atwood exhibited to the Boston Society of Natural His- 
tory, December 7, 1864, the lower jaw of a large shark, taken at Prov- 
incetown, Mass., in whose stomach nearly the whole of a large Sword- 
fish was found. Some ten or twelve wounds were noticed in the skin 
of the shark, giving an idea of the conflict. The shark was doubtless 
the tiger shark Galeocerdo tigrina. 
Couch was told by a sailor that he had watched with interest the anx- 
ious motions of one as it was followed closely and rapidly in all its turn- 
ings by a blue-shark. Twice did it leap above the surface to escape the 
near approach of its pursuer, but with what success at last the observer 
had no opportunity of knowing. 
Mr. John A. Thomson states that the Bill-fish (probably Tetrapturus 
albidus) is their especial enemy. Bill-fish, six to twelve feet long, appear 
about the last of the season, and their appearance is a signal that the 
Sword-fish are about leaving. 
44.—INVERTEBRATE PARASITES OF THE SWORD-FISH. 
Aristotle thus explains the leaping movements of the fish: ‘‘ The tunny 
and the Xiphia suffer from the estrus at the rising of the dog-star, for 
both these fish at this season have beneath their fins a little worm which 
is called estrus, which resembles a scorpion, and is about the size of a 
spider; they suffer so much from this torment that the Xiphias leaps 
out of the sea as high as the dolphin, and in this manner frequently 
falls upon ships.” 
This description of the parasite is somewhat vague; yet it is evident 
that allusion is made to one of the Lerneans or gill-lice, little crustae 
