7 6 



THE WONDER OF LIFE 



swimming ' worms', such as Sagitta like a glass arrow 

 in the water, a few Holothurians or sea-cucumbers which 

 have departed widely from the prevalent habit of their 

 class, a legion of Crustaceans often of surpassing beauty 

 of colour and form, a few insects 

 (Halobatidae) the last creatures 

 one would expect, such molluscs 

 as the sea-butterflies (Pteropods) 

 dainties which the whalebone 

 whale captures in countless 

 myriads in the great sieve which 

 hangs down from the yawning 

 cavern of its mouth, the similarly 

 light-shelled or shell-less Hetero- 

 pods and many actively swimming 

 cuttlefishes, such as the Argonaut, 

 some Tunicates like the Salps 

 (often swimming gently in long 

 transparent chains) and the 

 ' fire-flame ' (Pyrosoma) famous 

 for its luminescence, numerous 

 fishes such as flying fishes, a few 

 turtles and venomous sea-snakes, 

 such birds as Mother Carey's 

 Chickens and the flightless pen- 

 guins, and among mammals the cetaceans large and small. 

 This abbreviated roll may serve to suggest the representative 

 character of the pelagic fauna. Within the pelagic fauna it 

 seems right to include the petrels, since they are distinc- 

 tively ocean-wanderers, and very seldom come ashore 

 except for breeding. An ancient race, marked by their 

 protruding tubular nostrils and their compound bill of 



FIG. 25. Halobates, a 

 pelagic insect, one 

 of the Hemiptera. 

 (After Buchanan 

 White.) 



