26 SYNOPTIC COLLECTION. 



evidence to support the view that Rhizopods are more 

 primitive than Flagellata, or vice versa. He says : " Their 

 mutual affinities are very close, and together they stand as 

 the most primitive forms of modern Protozoa." 



While this may be true, a much more consistent ar- 

 rangement can be made if one begins with the Sarcodina, 

 as Calkins has done, and passes to the Mastigophora 

 (= Flagellata) and then to the most specialized Infusoria 

 (see p. 53). 



The whip-bearing Rhizopod (PI. n, figs, i, 2) repre- 

 sents an adult which combines the flagellum with the 

 Amoeboid pseudopodia. This flagellum is eight or ten 

 times the length of the body. When the motion changes 

 from creeping to swimming, the body lengthens as seen 

 in fig. 2. 



Amoeba quinta l shows a marked specialization of the 

 nucleus. PL 12, fig. i, is a young form with eight nuclei. 

 Whether the youngest stage has one nucleus cannot be 

 stated.' 2 PI. 12, fig. 2, represents an adult with twenty- 

 four nuclei (more existed but were omitted for the sake 

 of clearness), and the species may have hundreds, this 

 increase taking place, as the figures show, with the growth 

 of the animal. PI. 12, fig. 2a, represents the nucleus as 

 it appears before staining, which shows a differentiation 

 in structure from the nucleus of Amoeba proteus (PL 9, 

 fig. 3). The outer membrane lies over a peripheral layer 

 of granules, and the central portion is filled with a mass 

 which appears granular. When colored, the nucleus has 

 the appearance seen in PL 12, fig. 2, which is much more 



1 This species was described by Gruber as Amoeba proteus (Zeit- 

 schr. f. wiss. Zool., XXXVIII, 1883. p. 382), but afterward was 

 found by him to be Amoeba quinta (ibid., XLI, 1885, p. 205). See 

 his description of Amoeba proteus (ibid., XLI, 1885, p. 216, pi. XV, 

 figs. 43-45-) 



2 Gruber, Zeitschr. f. wiss. Zool., XLI, 1885. This author says 

 that what Biitschli has shown as such appears to belong to another 

 species of Amoeba. 



