1904] CURRENT LITERATURE 75 
Africa, and South America. The Stormberg beds are considered as of Rhaetic 
age, and four new species are described. The Uitenhage beds are considered 
as probably of Wealden age, and the fragmentary remains of nineteen species of 
plants are enumerated, of which two, a Nilssonia and an Araucarites, are described 
as new.—EDWARD W. BeErry. 
REED’ has made a cytological study of enzyme-secreting cells in corn and 
date seedlings. Sections of living tissue were compared with fixed material to 
avoid error. Torrey’s technique® is regarded faulty, and no evidence was found 
to support his observation that solid matter extrudes from the nucleus through 
interruptions of the nuclear membrane into the cytoplasm. In addition to a 
careful study of the literature and some valuable data in technique, the observa- 
tions of special interest are: ‘‘(1) In the resting condition the secreting cells of 
both Zea and Phoenix are crowded with relatively small proteid granules. As 
secretion begins these granules gradually disappear. In Zea this disappearance 
coincides closely with consumption of the endosperm; in Phoenix, however, the 
granules disappear long before the endosperm is dissolved. (2) The chromatin 
of the nucleus is small in amount at the beginning of secretion and increases as 
germination progresses. te changes are more noticeable in the case of Zea 
than in Phoenix.”—Raymonp H. Ponp. 
WIELAND? has we together a large array of facts to support the thesis 
that polar climate has been the major factor in the evolution of plants and animals. 
He shows that climatic changes of a character affecting life must in the course of 
time be at a minimum at the equator and at a maximum at the poles. He also 
thinks it reasonable that the origin of life itself took place at the north or at both 
poles; and that the Palaeozoic for various reasons was a period mainly of ‘“gen- 
eralized origins.”” From the origin of life down to the Mesozoic the north 
and south polar areas may have played a well-nigh equal part in creating a certain 
southward and northward stress; but beginning with the Mesozoic and “extend- 
ing to the glacial period, overwhelming evidence points to the polar origin and 
continuous outward dispersion from the north polar area of most of the great 
plant and vertebrate groups.” Among the illustrations of this the author calls 
attention to ‘‘the outward movement especially of conifers and dicotyls from the 
Arctic area for long periods of time.”—J. M. C 
WaceR,’° in a preliminary paper, has discussed the much debated question 
of the cell structure of the Cyanophyceae. He concludes that the central body 
7 REED, H. S., A study of the enzyme-secreting cells in the seedlings of Zea 
Mais and pleat dactylifera. Annals of Botany 18:267. 1904. 
RREY, Cytological changes accompanying the secretion of diastase. Bull. 
Torr. Bot. Club 29:421. 1902. 
9-WIELAND, G. R., Polar climate in time the major factor in the evolution of 
plants and animals. Am. Jour. Sci. IV. 16:401-430. 1903. 
10 WaGER, Haron, The cell structure of the Cyanophyceae. Preliminary paper. 
Proc. Roy. Soc. 72: 401-408. 1904. 
