1894 THE MICROSCOPE. 25 



laceous sacs ; Carpenter, flagellate chambers ; in which the 

 sponge animalcule "lives, moves and has its being." 

 These chambers according to Kent are the main charac- 

 teristics and chief points in the classification of sponges. 

 In shape these chambers differ in each species, some are 

 circular, others oval or semi-circular or pointed at each 

 end. These chambers are lined with the mucillaginous 

 sarcode — cytoblastema, having imbedded in them, facing 

 the center of the chamber, the sponge animalcule. In 

 shape they are round or oval cells, as a body, having 

 upon each a funnel-shaped hyaline collar of nearly the 

 length and breadth of the cell, with a flagellum extending 

 from the cell through and out of the collar. The discov- 

 ery of this zooid was made comparatively recently, 1866, 

 by a Pennsylvanian, Prof. H. James-Clark. These zooids, 

 like all infusorias, show the presence of a nacleus and 

 two contractile vesicles at the posterior end. Their func- 

 tions seem to be of a respiratory nature, but chiefly to 

 gather food. The flagellum, by rapid motion creates a 

 current, which striking the outside of the collar, which 

 also has a motion of a nature which caused Kent to call 

 it circulatory or cyclosis, makes all food particles adhere 

 thereto, from which they are drawn up over the rim and 

 thence along the inner surface into the body of the ani- 

 malcule. Before proceeding farther it should be re- 

 marked that each of these flagellate zooids is a separate 

 being without any bond or connection with its neighbor, 

 except being all attached to the same connective tissue, 

 the sarcode, or cytoblastema. The process of feeding 

 just related has been beautifully demonstrated by Kent, 

 by mixing the food water with carmine. It is claimed 

 that each zooid exudes excremental matter through its 

 food channel, but this like many other facts remains yet 

 to be verified. In this category of " claims " also be- 

 longs the location of the mouth at the root of the flagel- 

 lum. 



