6 Mr. W. Saville Kent on Prof. E. Haeckel’s 
investigation of the life-history of this collar-bearing group 
has yielded data abounding with evidence confirmatory of and 
parallel with that obtained by Messrs. Dallinger and Drys- 
dale relative to the life-history of the more simple Cercomo- 
nads, published at length in the ‘Monthly Microscopical 
Journal’ for the years 1873-74, some of the same having 
Monosiga gracilis, 8. Kent. 
A solitary Gymnozoidal Disco- 
stomatous Protozoon feeding on 
comminuted carmine: c¢, collar ; 
n, nucleus; jt, flagellum; cv, 
contractile vesicles; fig, food 
globules. The arrows indicate 
the direction of the current 
caused by the rotatory motion 
of the flagellum, and the course 
taken by the food-particles on 
striking against and adhering to 
the collar. The dotted line on 
each side of the flagellum marks 
the are described by its rotation. 
x 2000 diameters. 

been accumulated by me prior, and some subsequent, to 
the appearance of their very valuable contributions to our 
knowledge of these lowly organized types. 
My prolonged investigation of these hitherto little-known 
collar-bearing flagellate monads, together with a careful study 
of all other forms most closely approaching these in structure, 
