A Study of Sonic Gregarines 3 



The only references I have been able to find regarding a sim- 

 ilar occurrence of polycystid intestinal gregarines in the body 

 cavity are as follows : 



(i) Leidy (1851) writes, ''Grcgarina achactac ahbreviatae 

 . . . Habitation. — Proventriculus of Achaeta abbrcviata. The 

 same species I have observed in two instances on the exterior of 

 the ventriculus, free within the abdominal cavity. . . 



"'Grcgariiia blattae oricntalis. Habitation. — Within the intes- 

 tine and without, closely applied to its parieties, in Blatta 

 orientalis." 



(2) ]\Iagalhaes (1900), in referring to his proposed Gregavina 

 scrpentula from Periplaneta ainericana, notes that he finds it 

 "dans sa cavite viscerale, au niveau de I'origine des tubes de 

 Malpighi.'' 



I have found the same thing in Gregarina blattarum (Leidy's 

 G. blattae oricntalis) and in a gregarine from Eritcttix, so I am 

 inclined to regard the phenomenon as more common than the lit- 

 erature on gregarines would indicate. In Melanoplus, it is so 

 common as to constitute the body cavity a secondary site of 

 infection. 



In the case mentioned where so many gregarines were found 

 in the body cavity, I noted an incident which throws some light 

 on the possible' method of infection. In this case, the caeca, a 

 common site of infection, were filled with gregarines, and while 

 making a sketch of one of these, the tip of the caecum ruptured 

 and the line of gregarines which had been packed in there with 

 the protomerites pointing toward the tip rapidly made their way 

 out. There were sixteen gregarines, of which twelve were in 

 pairs. This at once suggests that the intestinal forms may at 

 times force their way through the loose tissue at the tip of the 

 caecum, and in fact this would seem to be the logical outcome of 

 packing this organ full of gregarines. And inasmuch as 

 gregarines of all sizes were found in the body cavity, it seems 

 probable that an opening once formed is afterward used to a 

 greater or less extent by other gregarines which may travel up 

 the caecum. 



151 



