213 
tronquées; deux dépressions buccales opposées l’une à l’autre com- 
mencant du milieu du corps et allant jusqu'à l'extrémité postérieure: 
l’un des bords de chaque dépression buccale est développé en une ex- 
pansion aliforme; de l’angle antérieur de chaque dépression buccale part 
un flagelle ayant à peu près la longueur du corps; de chaque côté 3 cils 
buccaux, insérée plus bas, ne dépassent pas la dépression buccale. Deux 
noyaux marginaux en forme de croissant, placés tout-à-fait à l’extrémité 
antérieure du corps et se touchant par leur partie antérieure renflée; de 
cette facon l’ensemble des deux noyaux figure une sorte de fer à cheval 
à concavité dirigée en arrière. 
A la division tout le matériel chromatique est employé à la forma- 
tion de chromosomes en forme de grains (16 pour chaque noyau). 
Dans le genre Hexamitus il y a des espèces libres et des espèces 
parasites; les genres Octomitus et Giardia ne renferment que des espèces 
parasites: les Trepomonas sont des Flagellés libres, mais certaines 
espèces (p. ex. 7. agilis Duj.) peuvent étre parasites facultatifs. 
Théodosie (Crimée). 
2. Copulation in Amoeba. 
By Ralph E. Hedges, Instructor in Zoology, Pennsylvania State College, with an 
appended letter by Maynard M. Metcalf, Oberlin College. 
(With 5 figures.) 
eingeg. 4. November 1913. 
While working in the Zoological laboratory of Oberlin College 
during the summer of 1912 I found a small species of Amoeba in a hay 
infusion which I was examining. These I took to be Amoeba limax. 
Although I was not working upon the Protozoa at the time, these 
Amoebae attracted my attention because they were particularly active, 
and because I several times saw two Amoebae move toward each other, 
touch and after remaining in contact for a few seconds move apart. 
In most casesit was impossible to distinguish a nucleus, for the Amoe- 
bae were small and filled with bacteria of which there was an abundant 
supply in the infusion. There was however very little debris upon the 
slide, so that the Amoebae could be seen very clearly. The material 
examined was not surface scum but was drawn up with a pipette from 
the sides of the receptacle and from the hay beneath the surface. 
The slide upon which I first found these Amoebae had not been 
under observation formore than ten minutes before I saw two Amoebae 
come into contact, and after remaining quiet in this position for perhaps 
twenty seconds, the distinct line of contact between the two individuals 
broke through for a portion of its length, and the protoplasm of one 
Amoeba flowed rapidly into the protoplasm of the other Amoeba. The 
