upon 'Luminous Animals. 291 
except in the flying insects, which by that means discover each 
other at night, for the purpose of sexual congress. 
Explanation of the Figures. 
Fig. i. The cancer fulgens, discovered by the Right Hon. 
Sir Joseph Banks, of the natural size. 
Fig. 2. The same animal magnified. 
Fig. 3. The medusa pellucens, also found by Sir Joseph 
Banks, represented of the natural magnitude. 
Fig. 4. The limulus noctilucus, discovered by Captain 
Horsburgh, considerably enlarged. 
Fig. 5. The luminous medusa, discovered by me, which I 
conceive to be the medusa hemispherica : it is shewn of the 
largest size I met with. 
Fig. 6. The central process of this animal's body magnified, 
in order to explain its structure. The thick tentacula in which 
it terminates are seen covered with small cups or suckers. 
Fig. 7. The beroe fulgens, discovered by me, shewn in its 
most elongated or relaxed form, which it assumes commonly 
when swimming quickly. 
Fig. 8. The same animal in the most contracted form. 
F.g. 9. The minute species of medusa, discovered by me, 
which is the most frequent cause of the luminous appearance 
of the sea. represented of the natural size. 
big. 10. I he same animal magnified, exhibiting a puckered 
or tucked-in appearance on one side. 
F : g 11. Is the animalcule discovered by Forster, of the 
natural size. 
Fig. 12.. The same, greatly magnified, to shew the intes- 
