STRUCTURE, ETC., OF PLEISTOPHORA PERIPLANETA, 615 
Observations on the Structure and Life-history 
of Pleistophora periplanete, Lutz 
and Splendore. 
By 
Ww. S. Perrin, B.A., 
Shuttleworth Research Student of Gonville and Caius College, 
Cambridge. 
With Plates 37 and 38. 
ContTENTs. 
PAGE 
1. Introduction : : : ; > JOS 
2. Material and Methods : 616 
3. Structure of the Vegetative Stages of Pietvopiers peeentintere 619 
4. Auto-infective Methods of Reproduction : : . 620 
5. Spore Formation : . 621 
6. Classification of Parasite ma Dineen of eaults ‘ 625 
7. Note on a hitherto undescribed Parasite (?) of Blatta or Pent alis 628 
8. Literature ‘ : : ; : . 629 
9. Description of Plate ; : : ‘ . 630 
Tue subject of this research, which is still in progress, is 
a Myxosporidian parasite of the ordinary black cockroach 
Periplaneta orientalis, found in bakehouses, college 
kitchens, and similar places. The presence of this parasite 
in the cockroach was first recorded by Schaudinn, who states 
(6) that the spores “eines Nosema” occur in the feces 
of cockroaches examined by him, and emphasises their 
similarity to the spores of Bacillus biitschlii, parasitic in 
the alimentary tract of Periplaneta orientalis. He de- 
scribes the presence of a polar capsule in these spores, and 
