90 
Tanks No. 6 and 22. 
in the Aquarium always die at the commencement of the winter. It 
lives on mollusks and crabs, which it grinds up with its sharp teeth, 
making so much noise in so doing, that it can be heard through the 
glass of the tank. It used formerly to share a tank with the Turtle. 
Fig. 165. Lichia glcmca, i/% nat. size. Tank 6. 
but never let the latter get a meal; and it had To be separated from the 
Lobsters, as it used to attack their eyes. 
We may now turn to the true pelagic "errant” forms, the Mackerels. 
Just as the Petrel and the Frigate-bird 
spend their life hovering over the endless 
expanse of the ocean, so the Mackerels 
rove about below the surface of the sea; 
approaching the coasts only periodically, 
when, however, they are caught in enormous 
numbers. 
Repeated trials to keep these shy but 
active fishes in the Aquarium have been 
unsuccessful. Nor can we expect the 
Tunny, or its ally the Swordfish, those 
two roving forms, to live in the cramped 
surroundings of our tanks. They all 
career about madly for a few hours and 
then die. Only one small genus of Mackerel, Lichia (Fig. 165), becomes 
accustomed to its captivity and lasts out like Balistes during the summer 
months; its skin shines like silver (tank 6). To the same order as the 
Mackerels belongs the "Cuckoo”, Capros (Fig. 166). Unlike its relations 
it lives at a depth of 30 to 40 fathoms, but it also thrives well in the 
shallow water of tank No. 22. 
REPTILES (REPTILIA). 
Besides Amphioxus and the numerous orders of fishes only one 
other vertebrate animal is found in the Aquarium, but this one is all the 
more imposing. It is the Caouana, Thalassochelys (Fig. 167), a Medi¬ 
terranean turtle, which grows to much more than 3 feet in length and 
may attain a weight of 400 pounds. It is found on all coasts of the 
Fig. 166. Capros aper, 
V 2 nat. size. Tank 22. 
