14 SYNOPTIC COLLECTION. 



of the elements of inorganic nature it is possible to con- 

 ceive of the origin of a mass of protoplasm like the young 

 Protamoeba (PI. i, fig. i). This is seen to be nearly as 

 large as the adult (fig. 2) , owing probably to rapid growth; 

 in P. schultzeana Hkl., however, the young form (PI. 2, fig. 

 i) is smaller than the full grown organism (PL 2, fig. 2). 

 The youthful form of Protamoeba primitiva, like the adult, 

 is a homogeneous, structureless mass of protoplasm or 

 sarcode, possessing no organs nor covering, and is known 

 as a cytode. No nucleus x is present, and no non-con- 

 tractile or contractile cavities called vacuoles. 



Protamoeba schultzeatia differs from Protamoeba primi- 

 tiva by having the protoplasm differentiated into an outer 

 layer or ectosarc and an inner layer or endosarc, both of 

 which are extended to form irregular, knobbed, spherical 

 continuations, as seen in the drawings (PI. 2, figs. i~4a). 



Notwithstanding the extreme simplicity of structure of 

 Protamoeba primitiva, the organism has the power of lo- 

 comotion, as is well shown by PI. i, figs. 2, 3. A pro- 

 longation of the body, or pseudopodium, is extended and 

 the streaming of the protoplasm into it causes the animal 

 to creep over surfaces. This is probably one of the sim- 

 plest physiological modes of motion, and results in pro- 

 ducing a crawling type. 



The power of taking food by means of the pseudopodia 

 was not observed by Haeckel, who described this form, 

 although he proved that small particles were absorbed 

 into the protoplasm of the body. In other species of the 

 same genus the pseudopodia and body have been seen to 

 envelop the food and the function of digestion followed. 



1 Biitschli considers that Protamoeba (as well as all of its group 

 of Monera) has a nucleus, but that it was not detected at the time 

 this organism was studied, on account of the imperfect means of in- 

 vestigation which then existed. On the other hand, no nucleus has 

 been found in Protamoeba vorax by Gruber (stated by Rolleston and 

 Jackson, Forms of Animal Life, ed. 2, 1888, p. 916), or in Archerina 

 by E. Ray Lankester (Quart. Journ. Micr. Sci., XXV, 1885, p. 61), 

 and these investigators have carried on their researches with modern 

 appliances and according to modern histological methods. 



