DACTYLOSPHERIUM RADIOSUM. 67 
Dimensions variable : diameter of body usually about 
30; length of pseudopodia sometimes 120 », or over. 
In marshes and pools, amongst submerged vegeta- 
tion, and in moss on dripping rocks ; less common than 
Ameba proteus, with which it is often associated. 
The rayed disposition of the pseudopodia and their 
rigid habit are characteristic of this species. Fre- 
quently the arms are curved, bent at an angle, or 
waved. A pseudopodium in extending or retracting 
will sometimes assume a spiral form and remain rigid 
in that attitude indefinitely. The endoplasm, as a 
rule, is uniformly granular, and the chlorophyllous 
matter occupying it is sparser than in the common 
Amebe. 
Biitschli transferred this form to the genus Dactylo- 
spheriun. (which he named in error Dactylospheria), 
though it must be confessed that there are few points 
of affinity between it and D. polypodium, so that there 
is some ground for Vejdovsky’s view that it should 
form the type of a new genus which he named 
Astrameba. Penard, however (‘ Faune Rhiz. du Bass 
du Léman’), does not consider that either Dactylosphe- 
rium radiosum or D. polypodiuim should be separated 
from the true Am@be. 
2. Dactylospherium polypodium (Max Sch.) Biitschli. 
(Plate III, fig. 12; Pl. IV, fig. 12.) 
Ameba polypodia Max Scuvttze Organism. Polythal. (1854), 
t. vill, f. 21; F. E. Scaurze in Arch. f. mikr. Anat. XI 
(1875), p. 592, t. xxxvi; ALLMAN in Journ. Linn. Soc., 
Zool. XIII (1877), p. 276; Cravs Lehrb. Zool. (1885), 
ff. 11, 184, and (Enel. transl.) Text-book Zool. I (1884), 
p. 22, ff. 11, 121; Grouper in Zeits. f. wiss. Zool. XT 
(1884), p. 128; Mager in Rend. R. Ist. Lomb. (2) XXT 
(1888), p. 306; Herrwie Lehrb. Zool. I (1891), p. 149, 
f. 116; ed. 2 (1900), p. 160, f. 114; and (Eng. transl.) 
Man. Zool. (1903), p. 189, f. 119; Sepewicx Text-book 
Zool. I (1898), p. 4, £. 2; Jorpan & Kuttoe Anim. Life 
(1900), p. 8, f. 4; Cazxins Prot. (1901), p. 80. 
