state they are yellow and roll up and down the Malpighian tube with 
the aow of its contents. Sometimes they are very numerous, and can 
be seen at once on examining the intestines. 
VI. THE FORMATION OF THE SPOROZOITES 
While in the intestine the barrel-shaped sporocyst gives rise, in its 
interior, to eight rod-shaped sporozoites. These are at first found tied 
together by their ends like a bundle of cigars or bananas, so that when 
viewed from above the sporozoite gives the appearance of eight small 
separate circles within a circle. Up to the present it has been 
impossible to separate these sporozoites or to stain them, but when the 
sporocyst passes into the rectum of the flea it ruptures, and t e 
sporozoites are set free with the faeces. The ultimate destination o 
the sporozoites has not been traced, but they are passed with t 
faeces. Whether, as stated before, there is a further ^ ° 
schizogony, or whether the sporozoites are eaten directly by t e 
larva and a new cycle of sporogony started, it is not possible to say 
But the flea larva is difficult to obtain, and still more ^ 
dissect. During two years' work with dog fleas the num er 
infected with this parasite was 38 per cent. 
I suggest as a name for this Gregarine, ctenocefhaLi 
canis. 
