10 



THE AMERICAN MONTHLY 



[January, 



the fine adjustments are of the pris- 

 matic or dove-tail form, with broad 

 bearings, to insure rigidity. 



The horseshoe base is reversible, 

 so that greater steadiness can be in- 

 sured \vlien the stand is used in the 

 horizontal position. This base may 

 be removed and a polished walnut 

 foot substituted for it, thus con- 

 verting the instrument into a con- 

 venient class-microscope. 



We can speak well of the design 

 and construction of the stand. 



Inclined as in the illustration, it 

 measures 35 ^"^- in height. 



It is sold, with the accessories 

 mentioned in this article, for $45.00. 



The makers of this stand have 

 worked out the following series of 

 objectives, which we describe in their 

 own words, not having personally 

 examined them. The ^-inch of 

 32 ° resolves up to No. 5 of Moller's 

 balsam plate; the ^^-inch of 115° 

 up to No. 13, and the -l-inch of 

 120° up to No. 14 of the same 

 plate. 



The Simplest Forms of Life.^- 



BY B. EYFERTH. 



[By republishing this work in 

 English, the Editor believes that 

 the labor will be best appreciated 

 by the amateur collector. To the 

 advanced student this classiti cation 

 will not be satisfactory, in every 

 respect. However, there is no ele- 

 mentary work of equal value to the 

 general student in English, or in 

 any other language. In carrying 

 out this translation, the plan of 

 arrangement in the original will 

 not be closely followed. The work 

 itself opens with the Algte, after 

 which follow the Rhizopoda. The 

 classification of the chlorophylla- 

 ceous Algae has been given in the 

 American Quarterly Microscopical 



* Translated from the German, by the Edi- 



Journal, and, therefore, will not be 

 reprinted in this journal at present. 

 The temporary omission of this part 

 of the work, will be amply compen- 

 sated for by the " Notes on Fresh- 

 Water Algse" which will appear 

 from time to time. 



Our first installment will be the 

 classification of the Rhizopoda, 

 after which will follow that of the 

 Infusoria. 



Dimensions are given in milli- 

 meters. — EDrroR.] 



Rhizopods. 



The bodies of rhizopods consist 

 of a homogeneous, nucleated plas- 

 ma. Dujardin called this substance 

 sarcode, Max Schultze and Colm 

 have shown that it is identical with 

 the plasma of plants. The rhizo- 

 pod body has no constant form, is 

 soft, and projections (pseudopodia) 

 constantly stretch out from the sur- 

 face and are retracted. These pseu- 

 dopodia serve for locomotion, and 

 also for seizing food. In some spe- 

 cies the pseudopodia are very fine, 

 branched, sometimes flowing to- 

 gether — anastomosing ; in others 

 they are thick, finger or lip-like. 

 AVithin the body are found many 

 small particles, generally one or 

 more nuclei, often Math prominent 

 nucleoli ; also one or more vacuoles. 

 Generally there can be seen an 

 endosarc and ectosarc. Many rhizo- 

 pods surround themselves with a 

 covering, which is either secreted 

 from the body-mass or formed of 

 foreign material. The covering has 

 an opening for the extrusion of the 

 pseudopodia, which also affords an 

 entrance for the particles of food. 

 The naked amoBbse simply envelop 

 their nutriment. In either case, di- 

 gestion takes place by the direct con- 

 tact of the food with the body-mass. 

 Little is known of the reproductive 

 process ; as yet only simple division 

 has been observed. 



