NOTES AND LITERATURE. 



GENERAL BIOLOGY. 



Plankton of the Illinois River.^ — Probably the most extensive 

 study of the plankton of any inland waters is contained in Kofoid's 

 report on the organisms of the Illinois river for the years 1894 to 1899, 

 The period of minimum productivity of plankton is January and Feb- 

 ruary ; this is followed by rising productivity which reaches its 

 maximum in April, after which there is a gradual decline to win- 

 ter conditions. Area and depth showed litde relation to plankton 

 production. Young waters from springs and creeks contain little 

 plankton, but these waters when impounded in backwater reservoirs 

 develop an abundant plankton. Fluctuations in hydrographic condi- 

 tions, temperature, and light afifect plankton production. Submerged 

 vegetations tends to diminish the production of plankton. The 

 plankton of the Illinois River is largely autonomous and may be esti- 



the river fisheries show some correlation. 



Where did Life begin ? ^— A second edition of Scribner's little 

 book, which attempts to locate the region where life first appeared on 

 the globe, has just been issued. The argument, now familiar to most 

 readers, turns on the gradual cooling of the earth's crust. Naturally 

 the first parts cooled would be the polar regions and here life may 

 have first originated. No good reason is given for selecting the 

 northern rather than the southern regions as the real centre nor is the 

 question of land and water in these regions sufficiently considered. 

 Since primitive organisms were without doubt water-inhabiting, the 

 possibility of a land-covered surface in the region where they were 

 supposed to originate is not without significance. Inconclusive as 

 the argument really is, the whole treatment of the subject is sugges- 

 tive and stimulating. 



' Kofoid, C. A. The Plankton of the lUinois River, i894-j899- P*- ^- Q"^"" 

 titative Investigation and General Results. Bu//. III. State Lab. Nat. Hist., Vol. 

 7. Art. 2, pp. 95-629, 50 pis. 



' Scribner, C. H. Where did Life Begin ? New York, Scribner's. 1903, i2T0. 

 75 pp. 



397 



