Zoolofiy and Botany. 463 



the author concludes "that in the excitatory relation between 

 protoplasm and the external world and the effects of such excita- 

 tion on protoplasm we have an adequate physiological basis for 

 organismic pattern and for the physiological continuity of devel- 

 opment." w. R. c. 



5. The Cactacecv: Descriptions and Illustrations of Plants of 

 the Cactus Family; by N. L. Britton and J. N. Rose. Volume^ 

 II, pp. vii, 289, with 40 plates (82 colored) and 304 text-figures. 

 Washington, 1920 (Carnegie Institution, Publication 248, Vol- 

 ume II). — The second volume of this important work fully main- 

 tains the high standard set for it by the first (see this JoLirnal, 

 49' 222). Of the eight subtribes into which the authors divide 

 the very large tribe Cerese, only the first two, the Cereanas and 

 the Hylocereana?, are here discussed. The Cereanae are erect 

 or bushy cacti and include 138 species divided into 38 genera; 

 the Hylocereana; are vine-like cacti and include 49 species divided 

 into 9 genera. Of the genera recognized 18 are monotypic, 22 

 of the others have 10 species or less, while the following genera 

 are represented by more than 15 species apiece : Gereus, Cephalo- 

 cereus, Lamaireocereus, Trichocereus, Harrisia, Hylocereus and 

 Selenicereus. The new genera proposed number 19, of which 

 eleven are monotypic; the new species proposed number 48. 

 Perhaps the most striking of all the species described is the 

 giant cactus, Carnegiea gigantea, of Arizona and the adjacent 

 parts of California and MexicO'. This remarkable plant with its 

 erect columnar trunk sometimes attains a height of 12 meters 

 and a diameter of over half a meter. Other interesting and 

 attractive cacti are the night-blooming cereuses, of which Hylo- 

 cereus undatus is the best known. Some of the most beautiful of 

 the colored plates, all of which were executed by Miss M. E. 

 Eaton, represent the large and showy flowers of this and similar 

 species. a. w. e. 



6. Phytoplankton of the inland lakes of Wisco7isin. Part I. 

 Myxophycece, Fhaeophycece, Heterokontece, and Chlorophycece 

 exclusive of the Desmidiacece; by Gilbert Morgan Smith. Pp. 

 243, 51 plates. Madison, Wisconsin, 1920 (Wisconsin Geologi- 

 cal and Natural History Survey, Bulletin No. 57). — The numer- 

 ous lakes of Wisconsin have afforded an exceedingly favorable 

 field for the study of our fresh water plankton, and Professor 

 Smith 's volume is an important addition to our scanty knowledge 

 of the subject. Over two hundred lakes were investigated, the 

 plankton being collected by means of nets with very fine meshes. 

 After a very useful key to the genera, based on vegetative char- 

 acters, the species observed are fully described, together with the 

 genera and higher groups under which they are distributed. 

 Wherever necessary, specified keys to species, genera or other 

 groups are included. In all 227 species are recognized, 54 belong- 

 ing to the Myxophycece (or blue green algcie), 18 to the Phaeophy- 

 ceas (or brown alga^) , 10 to the Heterokontea^, and the remainder 



