8 Frot. 
PROTOZOA. 
and sporules in the protoplasm ; pseudopodia digitate, hyaline, with- 
out granules, now and then with vacuoles. Propagation through division, 
sporules, and zygosis [?]. Largest size equalling that of a hemp- 
seed ; devours minute worms and Crustacea^ diatoms and other micro- 
organisms and substances. 
Troglodytes zoster^ Gabriel (9), is a minute (0.02 mm.) monostomatous 
monothalamian living in moist earth ; it possesses an ovoid hyaline struc- 
tureless shell, with a narrow slit-like orifice ; a nucleus in the ab-oral non- 
granular portion of the plasmodium, two larger and two smaller contrac- 
tile vacuoles in definite places ; a girth of granular substance, of which the 
granules are dispersed rhythmically over the plasmodium, and again with- 
drawn (especially immediately before the period of propagation) ; loboso 
and filiform pseudopodia, &c. The first step necessary for propagation 
is the copulation of two individuals meeting each other ; it consists in the 
formation, through confluence of the pseudopodia, of an intermediate con- 
necting body in which an exchange of substance probably takes place ; and 
is followed by the separation of the individuals, whose plasmodium now 
becomes the seat of changes of substance and remarkable vital phenor 
mena, and undergoes a sort of concentration ; the nucleus and nucleoles 
disappear, a sort of irregular segmentation takes place, and the plasmodium 
is metamorphosed into a “chagrin” of minute protoplasmic nodules 
or gemmules, which are set free through the disintegration of the plas- 
modium and the dissolution of the shell. These gemmules take 
the character of “ Monostigma'’' being provided with a single vacuole ; 
t>y “zygosis,’’ viz., a complete fusion of two individuals, they are 
developed, increasing in size all the while, into “ Diplostigmay' which 
through the successive formation of nucleus, shell, the two large contrac- 
tile vesicles, and protrusion of the pseudopcdia, are transformed into 
typical adult Troglodytes. Analogous modes of evolution are character- 
istic of other Mhizopoda living under similar circumstances. The vital 
phenomena, internal changes of structure, and movements accompanying 
the passage from one of these phases of existence to the other, are 
observed with remarkable delicacy and described with minute accuracy. 
Calcarina hispida^ sp. n., Brady (4), Loo Choo Islands. 
Hertwig (10) has ascertained the existence of a single nucleus or several 
“ nuclei ” in several perforate or imperforate Foraminifera, thus remov- 
ing the last barrier between the fresh-water and marine Mono- and Poly- 
thalamia, which he reunites under the name of Thalamophora, and divides 
into T. imperforata and perforata. The observations were made on 
young Miliolce (Spiroloculina), liotalice, and Textilarice. The young speci- 
mens of Miliola and Rotalia are only provided with a single nucleus ; 
more advanced ones with 1-3 in each of the older chambers ; while only 
a single nucleus could be detected in 5-13-chambered Textilarice. Thus 
there is no definite relation between the number of the nuclei and that of 
the chambers. Schulze (16) has likewise discovered a nucleus in Entoso- 
leniay and ascertained its presence in Rotalina and Polystomella ; in the 
latter genus, it is situated in one of the middle-aged chambers ; rarely, there 
are 2 or 3 in contiguous chambers or in chambers separated by a single 
chamber; it is evident that, during the growth of the Foraminifer, the 
