128 GC. CLIFFORD DOBELL. 
daughter-cells which have not separated. These observa- 
tions were made quite independently by Barker, Guilliermond, 
and others. A comparable process is also to be seen in the 
Algw—e. g. Spirogyra—where adjacent cells may some- 
times conjugate and form a zygospore. And there are further 
analogies to be found in the autogamy of the Protozoa (Bodo, 
Trichomastix, etc.), and the curious form of partheno- 
genesis sometimes seen in the Metazoa—for instance, in 
Artemia, according to the well-known description of Brauer. 
The breaking up of the intermediate portion of the spiral 
may be regarded as a nuclear reduction—though it has yet 
to be proved that the filament really consists of chromatin. 
Similar filaments, consisting very probably of chromatin, 
occur in allied organisms, for example, in B. maximus 
buccalis (Swellengrebel), in Spirocheta balbianii 
(Perrin), and in Spirillum giganteum (Swellengrebel) 
(cf. also B. spirogyra, infra). 
II. Bacillus spirogyra,n.sp. (PI. 6, figs. 20a, 8, c.) 
I have found this Bacillus on several occasions in the 
rectum of frogs and toads. In the living condition it is an 
actively motile rod, of high refractivity. It shows no internal 
structure until stained—a circumstance which I believe to be 
due chiefly to the great thickness of its pellicle. In length 
the organism measures about 8—11, and in breadth about 
1:5—2y. Itis, therefore, a bacillus of considerable size. 
Upon staining the organism some additional points in its 
morphology can be made out. The very thick pellicle stains 
pink with Giemsa, and inside the organism a spiral filament 
is seen, which is stained like chromatin. That is to say, it 
becomes red or purple with Giemsa, black with iron-hema- 
toxylin, etc. I believe it to be of a nuclear nature. It is 
reminiscent of the spiral structure described by Swellengrebel 
in B. maximus buccalis (see Pl. 6, fig. 20a). 
The method of division is by septation, as in B. biitschlii. 
Before division the nuclear spiral becomes more coiled, and 
