178 THE AMERICAN MONTHLY [August, 



goes and that it will be of service to the beginner, helping him to 

 gain enough knowledge of the classification to lead him to con- 

 sult Haeckel's work itself if he finds the subject interesting. The 

 trouble with the strictly accurate key is that it is apt to be so full 

 as to discourage the beginner, especially if he has but little time 

 to devote to microscopical study. I am judging others bv myself 

 and venturing to put before them what has proved helpful to me. 

 But if in any case the student finds himself at a loss let him go to 

 work in turn and make a better scheme for the good of his fel- 

 lows, at least so far as to remedy the defect in that particular. 

 Trusting, therefore, that the readers of the Journal will under- 

 stand m}- purpose and make all allowances, I shall try to give the 

 more important points of the classification as far as I have been 

 able to make them out. 



In the number of the Journal for January, iSSS, I mentioned 

 these four orders oi Rhizopods^ namely. 



The Protoplasta^ 

 The Heliozoa, 

 The Radiolaria^ 

 The Foraniiiiifera ; 



and I said that these four fell again int(j two main subdivisions, 

 founded on locality, namely, the fresh-water and the marine 

 Rhizopods ; the Protoplasta and the Heliozoa forming the first, 

 the Radiolaria (including the Rolycysthia) and the Foraini- 

 7iiffra forming the second section. I remarked further that it would 

 take us too far to enter into the minor classification of the marine 

 Rhizopods. Little did I dream then how huge the marine sub- 

 division was, my meaning being simply that the fresh-water 

 forms were sufiicient for our purpose at that time. Even when 

 I decided to write on the marine section it seemed to me that it 

 would be feasible to treat of both the divisions in that section in 

 one article. At any rate I thought the Radiolaria could be dis- 

 posed of in short order, and the Micrographic Dictionary encour- 

 aged the idea, as it gave but half a colnmii to the Radiolaria 

 and scarcely a dozen figures of the genera. Even Carpenter, 

 while he enlarged very considerably on the Micrographic's mea- 

 gre account, gave but little space to the Radiolaria as compared 

 with the Fora7ninifera. So that I was totally unprepared for 

 the facts as revealed by the latest edition of the Encyclopa'dia 

 Brittanica. The moment I glanced over the description there I 

 saw that it would be useless to attempt to take both the Foranii- 

 nifera and the Radiolaria at the same time, for the Encyclopie- 

 dia enumerated no less than forty-nine genera of the Radiolaria 

 alone, and even these it said were selected. And then when I 

 gained access to Haeckel's splendid work I was amazed beyond 

 all bounds and ready to drop the whole subject, for he stated that 

 the number of genera was no less than 739 with over 4,000 spe- 

 cies ! This, I am sure, will surprise some of you as much as it 



