42 PROCEEDINGS OF THE ACADEMY OF [Jan., 



Fig. 74. — Camera outline. Iron hematoxylin and eosin. Mouse 106, 9 hours. 



Male. Stage showing microgametes. The parasite is unusually small. 



This stage is very rare in periods as short as 9 hours. 

 Fig. 75. — Camera outline. Wright's stain. Mouse 152, 18 hours. Male. 



Stage showing microgametes. 

 Fig. 76. — Camera outline. Iron hsematoxylin. Mouse 152, 18 hours, int. —1. 



Optical section of the same stage of development as shown in fig. 75. 

 Fig. 77. — Free-hand sketch. Thionin and acid fuchsin. Mouse 247, 4 hours, 



int. 14. Female, typical early stage. 

 Fig. 78. — Camera outline. Iron hsematoxylin and acid fuchsin. Mouse 106, 



9 hours. Female. Cytoplasm mottled. Karyosome shows several black 



granules. This is possibly a very early stage of maturation. 

 Fig. 79. — Camera outline. Iron hsematoxylin. Mouse 113, 9 hours. Typical 



female. 

 Fig. 80. — Free-hand sketch. Iron hsematoxylin. Mouse 113, 9 hours. Female. 

 Fig. 81. — Camera outline. Iron hsematoxylin and acid fuchsin. Mouse 106, 



9 hours. Female. Cytoplasm shows the alveolar structure which can 



frequently be made out in the females. Nucleus shows a ring of deeply 



staining granules lying around the membrane. These are taken to represent 



that part of the chromatin which is rejected during maturation. 

 Pig. 82. — Camera outline. Delafield and acid fuchsin. Mouse 106, 9 hours. 



Female, same phase as shown in fig. 83. The granules lying in the mouse 



cell are not believed to have anything to do with the parasite. 

 Fig. 83. — Camera outline. Iron hsematoxylin and acid fuchsin. Mouse 106, 



9 hours. Female. Later stage of maturation. 

 Fig. 84. — Camera outline. Iron hsematoxylin and acid fuchsin. Mouse 145, 



11 j hours, int. — 1. Female. Late stage of maturation. 

 Fig. 85. — Camera outline. Wright's stain. Mouse 146, 11? hours, int. — 1. 



Female. Late stage of maturation. 

 Fig. 86. — Camera outline. Iron hsematoxylin and acid fuchsin. Mouse 120, 



10! and 17 hours. Female, late stage of maturation. 

 Fig. 87. — Camera outline. Wright's stain. Mouse 146, 11! hours, int. — 1. 



Female, late stage of maturation. 

 Fig. 88. — Camera outline. Wright's stain and eosin. Mouse 152, 18 hours, 



int. —2. Mature female or macrogamete. 

 Fig. 89. — Camera outline. Iron hsematoxylin and acid fuchsin. Mouse 120, 



10| and 17 hours. Macrogamete. 

 Fig. 90. — Camera outline. Iron hsematoxylin and acid fuchsin. Mouse 145, 



Hi hours, int. — 1. Macrogamete. 

 Fig. 91. — Camera outline. Wright's stain and eosin. Mouse 152, 18 hours, 



int. —2. Macrogamete. 

 Fig. 92. — Camera outline. Wright's stain and eosin. Mouse 152, 18 hours, 



int. —2. Two microgametes are seeking to fertilize a macrogamete. 

 Fig. 93. — Camera outline. Wright's stain and eosin. Mouse 152, 18 hours, 



int. —2. Three mae.rogamet.es are shown, in each of which is a conspicuous 



chromatic element, taken to be the microgamete. 



Bibliography. 



Crawley, Howard. 1913. Initial stages of Sarcocystis infection. [Note 



presented before Helminthol. Soc. Wash., D. C, Feb. 6.] <Science, N. Y., 



n. s. (952), v. 37, Mar. 28, p. 498. 

 - 1914. Two new Sarcosporidia. <Proc. Acad. Nat. Sc. Phila., v. 66 (1), 



Jan.-Mar., pp. 214-218, 1 fig. 

 — 1914. The evolution of Sarcocystis muris in the intestinal cells of the mouse. 



(Preliminary note.) <Proc. Acad. Nat, Sc. Phila., v. 66 (2), Apr.-Aug., 



pp. 432-436, pi. 15, figs. 1-12. 

 Ekdmann, Hii. H)10. Die Entwicklung der Sarcocystis muris in der Musku- 



latur. <Sitzungsb. d. (lesellsch. naturf. Fr. zu Berl. (9), Nov., pp. 377-387," 



figs. A-E, pis. 18-19, figs. 1-14. 



