428 



THE AMERICAN NATURALIST [Vol. XLII 



deserves more than the superficial description which the author 

 gives. It is difficult to conceive how the budding process could 

 have been overlooked, for in Entamoeba under culture on agar, 

 this process is apparently the most common method of reproduc- 

 tion. It is quite probable Ibat development of the extruded so- 

 called "spores" as described is the actual development of such 

 buds. The finer details of si nurture were not made out, the origin 

 of chromidia uramdes and their fate are not described, owing, 

 possibly, as the author admits, to faulty technique (p. 418). 

 Much dependence is placed upon the ct/st, but there is no evi- 

 dence to indicate that the author is cognizant of the difference 

 between temporary and permanent cysts. Many instances 

 among protozoa might he cited of the wide difference existing 

 in the two types and in the same species, and Schaudinn and 

 others have previously called attention to these differences in 

 the parasitic rhizopods. Hence the cyst, as a feature in the 

 ident ideation of species as Walker gives them, loses it value. 

 Walker's lone; list of species finally, while a convenient summary 

 of the described amoeboid parasites, can not be accepted as 

 established, and his several "new'" species must share the same 

 fate, for in no case has the full life history— the only adequate 

 basis of species — been made out. When the full history is 

 worked out, these many so-called species will probably be re- 

 duced to mere varieties, or to a few species of the genus 

 Entamoeba. 



G. N. C. 



EXPERIMENTAL ZOOLOGY 

 Regeneration. 1 — Professor Korschelt has brought together 

 in compact, yet readable form, the more important results 

 on regeneration and transplantation in animals and plants. 

 No small amount of discrimination is required to put into 170 

 pages all the results so far obtained on regeneration both of 

 animals and of plants; yet Professor Korschelt has shown un- 

 usual judgment in selecting the essential and typical results of 

 the old and the recent work. Necessarily, much detail lias been 

 pruned away, yet the author has succeeded in bringing into 

 proper correlation many widely scattered facts. The more 

 theoretical and analytical sides of the problem occupy a very 

 1 Regeneration und Transplantation. By E. Korschelt. 1907. 



