THE PELAGIC FAUNA AXD FLORA. 



193 



(Fig. 115), though not uncommon in deep waters, are more 

 rarely thrown up on beaches. Professor Giglioli has dredged 

 them in the Mediterranean, and they have been dredged east of 

 Long Island by the United States Fish Commission. 



One of the most characteristic of the Atlantic pelagic types is 

 Sagitta (Fig. 116) ; as its name implies, it darts through the 

 water in search of its minute prey, which it seizes with its 

 gigantic jaws. Other worms, like Autolytus and Nereis, are 

 at times pelagic, while the large-eyed Argyope and the trans- 

 parent Tomopteris (Fig. 117) are constant attendants of the 

 surface fauna. Of Crustacea there are a host of minute pre- 

 datory forms, — Calanus, Mysis, Nebalia (Fig. 118), etc., — 

 regular scavengers of the surface, 

 and thousands of copepods, the main 

 object of whose existence seems to 

 be to keep themselves on hand as 

 food for the larger pelagic types 

 of Crustacea, like Euphausia and its 

 allies. We have certain forms of 

 pelagic fishes, the transparent Plagu- 

 sise, Leptocephali, and the like, some 

 species of which are only the young 

 of deep-sea forms. Pelagic species 

 of fishes often attain a large size, 

 such as the thunny, horse-mackerel, sword-fish, Orthagoriscus, 

 Coryphaena, Histriophorus, and others. The group of flying- 

 fishes is a true pelagic type, to which we might add some of 

 the migratory fishes, as the clupeoids and scombroids. Many 

 of the large types of sharks like the thrasher, basking shark, 

 and mackerel shark, are pelagic, and are met with at great dis- 

 tances from the coast. The skates, on the contrary, are nearly 

 all deep-water types, though they are occasionally seen hunting 

 near the surface. Finally, of the mammals, the whales, dol- 

 phins, and porpoises, dancing attendance on ships far out at sea, 

 complete our general enumeration of the pelagic types. 



Among the more minute types are the graceful globigerinse, 

 with their delicate arms, appearing like scarlet dots on the sur- 

 face of the sea. These swarm on warm, calm days. I had an 



Fig. 118. — NebaUa. 



