70 
Tanks No. ,10 and 12. 
Mediterranean, and feeds on fishes frequenting like itself the muddy 
bottoms of the sea. Its very indifferent flesh is eaten by poor people, its 
rough skin is used for graters, sheaths for knives, and other purposes. 
The true Rays have a flat body compressed from above, which has 
Fig. 120. Squatina angelus, i/io rat. size. Tank 10. 
Fig. 121. Torpedo ocellata, 1 Jq nat. size. Tank 12. 
on its upper darker surface the eyes and two openings leading to the gills. 
On the lower paler surface are situated the mouth, the nasal apertures 
and the gill-slits. They are all deep-sea forms and live on the smaller 
animals frequenting the bottom of the sea. 
The most interesting form is the Electric Pi.ay, Torpedo (Fig. 121, 
tank No. 12), which was known to the ancients for its curious power of 
