78 



THE A MERIL AX NA TURA LIST. [\'< . i . X X X \' 1 1 1 . 



acquainted with Bower's magnificent series of nion()<,Maplis on this 

 subject, but we can find no reference to them in the book. 



The idea of an imbedded sporangium seems to have been taken 



either Goebel or Strasbur-er, will show that [)oth of these authors 

 consider the whole of the superficial tissue of the loculus, as forming 

 the wall of the sporangium, and the whole pollen sac as the direct 

 homologue of the microsporangium of the pteridophytes. 



It seems to be also assumed, although we can see no warrant for 

 this, that the nucellus represents something more than a macrospo- 

 rangium. 



As might be expected, the development of the embryo-sac is given 

 very complete treatment, the chapter dealing with this important topic 

 comprising fifty pages, of which four are devoted to the bibliography. 

 Much of the matter in this chapter is taken from the numerous papers 

 which have been issued from the botanical laboratory of the Univer- 

 sity of Chicago, and many of the copious illustrations are drawn from 

 the same sources. This chapter will probably be fovmd the most 

 useful in the book. The extensive literature of the subject has been 

 carefully reviewed, and on the whole, little exception can be taken to 

 the references selected to form the bibliography appended to the 

 chapter. A great many facts are presented, and although the very 

 number may be rather confusing to one unfamiliar with the subject, 

 the chapter will nevertheless, give the student an excellent idea of the 

 present status of our knowledge of the development of the embryo- 



The male gametophyte, naturally, has less space devoted to it, but 

 is sufficiently complete. We should like to call the authors' attention 

 to a mis-statement. The male prothallium of Sparganium is not 

 referred to at all in the preliminary paper quoted, but was first 

 described in the more complete monograph ^ published subsequently, 

 and which seems to be unknown to the authors. 



Chapters seven and nine are concerned respectivelv with Fertiliza- 

 tion, The Endosperm, and The Embryo. 



The chapter on Fertilization is well up to date, and gives a clear 

 account of the latest studies upon this important topic. 'J^he chapter 

 on the Endosperm is not so satisfactory, a number of more or less 

 important omissions being noted. Thus no mention is made of the 

 peculiar behavior of the lower endosperm nucleus in Naias. 



