ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 459 



New Sarcosporidia.* — Howard Crawley describes Sarcocystis leporum 

 sp. ri. from the muscles of the arm and shoulder of a very old rabbit. 

 The spores show two very clear-cut oval areas, the nucleus in the posterior 

 half and the clear faintly-stained area or rostrum in front. It is prob- 

 able that the function of the rostrum is to enable the spore to drill its 

 way into the intestinal epithelium of its host. Another new species, 

 S. setophagse, was discovered by Hassall in the muscles of a redstart 

 (Setopkaga ruticilla) and is now for the first time described. 



Development of Sarcocystis muris.f — Howard Crawley has studied 

 the earlier stages of this parasite in the intestinal cells of the mouse. 

 The spore in the intestine is naked and displays very energetic twisting 

 and boring movements. It forces its way into a cylindrical epithelial 

 cell and becomes banana-like ; male and female forms are differentiated, 

 and those that are clearly females show phenomena which suggest 

 maturation. In the spaces beneath the epithelial cells a condition was 

 found which looks like a macrogamete fertilized by a microgamete. 



* Proc. Acad. Nat. Sci. Philadelphia (1914) pp. 214-18 (1 fig.). 

 t Proc. Acad. Nat. Sci. Philadelphia (1914) pp. 432-6 (1 pi.) 



