240 BULLETIN OF THE UNITED STATES FISH COMMISSION. 



favorable conditious of light and temperature it may hare three broods 

 a month, or even a greater number, the larger species having as many as 

 forty or fifty eggs at once." 



The remarkable fecundity of the Copepoda explains the extraordinary 

 abundance of the free-swimming species upon the high seas, and even 

 bays, where vast schools of these crustaceans become, in turn, the food 

 of vast schools of herrings, menhaden, and shad. Doubtless, the move- 

 ments of these fishes on the high seas are determined by the abundance 

 of their favorite food in various localities; that, like the whale, they 

 seek their marine pasture of crustaceans, as argued by Mobins. Even 

 larger forms of fishes, such as the huge basking shark {Cetiorhhms max- 

 ■imus), has its branchial apparatus adapted to capture small jielagic 

 organisms, in the same way as the Clupeoids. The jirodigious numbers 

 of herrings and menhaden is a jiroof of the abundance of the minute 

 pelagic organisms upon which, with scarcely a doubt, it may be sup- 

 posed they subsist. It is also not improbable that the vast schools of 

 pelagic Entomostracans are in pursuit of still smaller protozoan prey, 

 upon which they subsist aiul maintain their marvellous reprodu<;tive 

 powers. Moseley, in his "Notes by a Naturalist on the Challenger," ob- 

 serves: "The dead pelagic animals must fall as a constant rain of food 

 upon the habitation of their deep-sea dependents. Maury, speaking of 

 the surface Foraminifera, wrote, 'The sea, like the snow-cloud, with its 

 flakes in a calm, is always letting fall upon its bed showers of micro- 

 scopic shells.'" Moseley records that he estimated, from experimental 

 data, that it would take four days and four hours for a dead Snliya to 

 fall to the bottom where the sea was 2,()()() fathoms in depth. The deep- 

 sea fauna is probably well supi)lied with food from such sources. The 

 researches of Mr. John Murray of the Challenger fully confirm and 

 greatly expand the significance of the views of lieutenant Maury in 

 relation to the destiny of the marine foraminiferpJ shells. Wyville 

 Thompson, Voyage of the Challenger, I, 210, observes: "Mr. Murray 

 has combined with a careful examination of the soundings a constant 

 use of the tow-net, usually at the surface, but also at depths from ten to a 

 thousand fathoms ; and he finds the closest relation to exist between 

 the surface tauna of any particular locality and the deposit which is 

 taking place at the bottom. In all seas, from the equator to the polar 

 ice, the tow-net contains GlobujerinceJ^ Some of these surface Forami- 

 nifera are relatively large, Orhnlina universa being as much as a fiftieth 

 of an inch in diameter, and hence of a sufficient size to be preyed upon 

 by a larger arthropod. The remarkable Pyrocystis nocUluca, discoA^ered 

 by Mr. Murray, and nearly a millimeter in diameter, is another inter- 

 esting surface form, as is also the P. fusiformh^ which is allied to it. 

 Both are phosphorescent surface swimmers, and fall within the reach of 

 other surface animals as a probable source of food. To these may be 

 added the curious group of the Challengerida, together with the whole 

 of the Badiolariaj "svith their siliceous shells, which, in the warmer parts 



