RHIZOPODA. 
ProL 13 
Rpecies from N. America, viz. : A. vulgaris, p. 170, pis. xxvii. & xxviii. 
figs. 1-13 ; discoides^ig 173, pi. xxviii. figs. 14-38; mitrata, p. 175, pi. xxix., 
perhaps = glohosa, Archer ; dentata, p. 177, pi. xxx. figs. 10-19 ; artocrea, 
p. 178, pi. xxx. fig. 1-9. 
Arcp.Ua vulgaris : stages of its development described and figured by 
G. Cattaneo, Atti Soc. Ital. xxi. p. 331, pi. vi. The germs which result 
from conjugation become nucleated and amoeboid, and acquire a con- 
tractile vacuole ; their protoplasm then becomes differentiated into endo- 
and ecto-plasm ; in the fourth stage, the movements become less active, 
the ectoplasm becomes striated, and the nucleus forms round the nucle- 
olus; in the eighth, the young Arcella is stationary, and consists of ecto-, 
meso-, and cndo-plasm, with one, and afterwards several, contractile 
vacuoles ; lastly, the shell is formed, the form becomes regular, the 
circular opening and several nuclei appear. 
Arcella viridis, from Lombardy, described by Maggi, Atti Soc. Ital. 
xxi. p. 316. 
Centropyxis aculeata, (8) p. 180, pi. xxx. figs. 20-34, pis. xxxi. & xxxii. 
figs. 29-37, N. America ; the spineless ecornis, Ehrenberg, is to be regarded 
as a variety. 
Cochliopodium (S). 2 species from N. America, viz.: C. bilimbosum, 
p. 184, pi. xxxii. figs. 1-25 ; vestiturri; p. 188, pi. xxxii. figs. 26-28. 
Pamphagus (8). 4 species enumerated from N. America, viz. : P. muta- 
hilis, p, 191, pi. xxxiii. figs. 1-9; hyalinus, p. 194, pi. xxxiii. figs. 13-17, 
and 2 new species. 
Dinamceba mirabilis, (8) p. 81, pis. vi. & vii. figs. 1-11, invested with 
a jelly-like cloak, beset with cilia resembling Bacteria ; swallows long 
A Igce ; N. America. 
Uramoeba, Leidy (8). Two species in N. America : U. vorax, p. 67, 
pi. ix. figs. 1-12, local; U. botulicauda, p. 71, pi. ix. figs. 13-17, very likely 
the young of preceding. 
ximoeha (3). 4 distinct N. American species admitted, viz. : A. proteus, 
p. 30, pi. i. figs. 1-8, pi. ii. figs. 1-13, pi. iii. figs. 22-25, pi. vii. figs. 13-19, 
pi. viii. figs. 17-30, the common Amoeba, its structure and physiology 
described; observed to swallow .d. verrMco.su, which broke up inside it; 
verrucosa, p. 53, pi. iii., sluggish habits ; radiosa, p. 58, pi. iv. figs. 1-18; 
villosa, p. 62, pi. i. figs. 9 & 10, pi. ii. figs. 14-16, pi. viii. figs. 1-16, doubt- 
ful whether yet found in N. America. 
Amoeba sabulosa, Leidy, (8) p. 73, = Pelomyxa villosa, sp. n. 
Amoeba princeps and terricola, in the Lake of Geneva, at the bottom ; 
Bull. Soc. Vaud. (2) xvi. p. 166. 
Amoeba hlattce, (8) p. 300, = Endamoeba, g. n. 
New genera and species : — 
Radiolaria. 
Acanthometra astroides, R. Hertwig, (7) p. 135, Messina. 
Heliosphcera insignis, id. 1. c. p. 168, pi. v. fig. 7, Messina. 
Diplosphoera spinosa, id. 1. c. p. 177, pi. v. fig. 2, Messina. 
Ceratospivis acuminata, id. 1. c. p. 198, pi. vii. fig. 2, Messina. 
Plagiacantha abietina, id. 1. c. p. 200, pi. vii. fig. 6, Messina. 
