588 



DEPTHS OF THE OCEAN 



barely be seen in the sea with the naked eye. The two last-mentioned 



forms are found in warm currents on the coast of Norway, and their 



presence is feared by the fishermen, because they very often spoil the 



herring which feed on them ; the shells are very slowly digested and the 



stomach-contents putrify when the her- ^__^ 



rings are salted, and then the whole herring ( . 



decomposes. Among the many warm- ^ 



water species Liniacina biilimoides is 



characteristic. The Cavolinidse include 



numerous forms with cornet-shaped shells. 



Clio pyramidata (Fig. 430) and Diacria 



trispinosa are very important forms, 



occurring in vast numbers, and their shells 



are very numerous in the deposits. Creseis 



Fig. 429. 



Lhnacina retroversa, Fleming. 

 (From Sars. ) 



Fig. 430. 



Clio pyra m id a ta, L 

 (From Boas.) 



acicula (Fig. 431) and Cavolinia gibbosa 

 (Fig. 432) are characteristic forms. 



The " whale's food," Clione liniacina 

 (Fig. 433), is specially abundant in north- 

 ern waters, and is better known than most 

 of the Gymnosomata. It is 3 or 4 cm. 

 long, perfectly transparent, with red shad- 

 ings and black stomach. In the Polar 

 Sea it may be seen swimming among the 

 ice-floes, but it occurs also in the Nor- 

 wegian Sea, in the Norwegian fjords, and 

 in the Atlantic south of Iceland. 



The majority of the pteropoda (both 

 species and individuals) are restricted to 

 warm water : in the Atlantic the northern limit for the warm- 

 water forms may be roughly drawn from the Bay of Biscay to New 

 York, and the southern limit from Brazil to the Cape. This area 

 is the real home of Clio pyramidata, C. aispidata, Creseis aciada, the 

 Cavolinidae, the Cymbulidae, Pneumoderma violaceum, Liniacina infiata, 

 L. lesueuri, L. biilimoides. As with the radiolaria and copepoda, many 



Fig. 431. 

 Creseis acicula, Rang. 

 (From Meisenheimer. ) 



