THE VORTICELLIDE. 85 
THE NATURAL HISTORY AND DEVELOPMENT OF 
THE VORTICELLIDA,* 
BY H. EH. FORREST, 
The Vorticells are familiar objects to almost everyone who possesses 
& microscope. Wherever there is water, salt or fresh, the various species 
are to be met with, differing in minor points, but all bearing a strong and 
unmistakable family likeness to one another. They are seen to the 
best advantage with a black background illumination, and when thus 
shown are perfectly lovely. The light seems to ripple and dance over 
their delicate milk-white forms, as the cilia lash the water into a hundred 
. eddying whirlpools. With lightning rapidity, first one and then another 
darts backwards, each tiny stalk coiling up like a python, then slowly but 
gracefully unwinds till at full stretch, when the ciliary wreath again 
displays itself. All is done, too, with the most perfect grace; nothing is 
clumsy or unwieldy in all their various actions, and few, if any, natural 
objects can vie with them for beauty. 
But their charms seem powerless to secure from Naturalists the 
amount of attention which they deserve, and they are usually passed 
over with merely a cursory glance, simply because they are common. It 
is the object of this paper to show that the history of the Vorticellida is 
a deeply interesting, as well as a fascinating study, and by describing 
what is already known of them to point out what avast field for original 
research lies open here for those who have the zeal and patience to 
penetrate a little more deeply into the subject than they have hitherto 
done. 
In order to render it as clear and concise as possible, my paper will 
be confined to four species, typical of four genera, and each will be 
treated of separately. These four species are :— 
(1) Vorticella nebulifera, [Plate I., Figs. 1 and 2.] Stalk long, 
contractile, not branched ; usually gregarious, 
(2) Carchesium polypinum, [Plate I., Fig. 3.] Stalk long, contractile, 
branched, spreading. Bells on one side of branch only. 
Description oF Ficures.—Puate I. 
1.—Vorticella nebulifera, expanded, x250 diameters. a contractile vesicle, b disc, 
c rim, d vestibule, e nucleus. 
2.—Vorticella nebulifera, contracted, x250 diameters. a nucleus. 
3.—Carchesium polypinum, x100 diameters. 
4.—Carchesium polypinum, stem of, x 250 diameters. 
5.—Carchesium polypinum, individual, x 250 diameters. 
6.—Epistylis lewcoa, x100 diameters. 
1.—Epistylis leucoa, individual, x250 Giameters. The arrows indicate the move- 
ments of the contents. 
8 and 9.—Vorticella, showing self-division, x 200 diameters. 
10, 11, and 12.—Vorticella, showing encystation, x 350 diameters. 
13.—Vorticella, showing acinetation, x 250 diameters. 
14.—Vorticella, free embryo, x 300 diameters. 
15.—Carchesium, showing gemmation, x 200 diameters. 
* Abstract of a paper read before the Birmingham Natural History and Micro- 
_ seopical Society, December 10th, 1878. 
+ Ehrenberg soe this species with bells on both sides of the branch, but thig 
is incorrect.—H. H 
oO 
