1916.] NATURAL SCIENCES OF PHILADELPHIA. 41 



Fig. 56.— Camera outline. Iron hematoxylin and acid fuchsin. Mouse 120, 

 lo' and 17 liours. Male. The chromatin occur- as small granules which 

 appear to be migrating toward the periphery. 



Fig. . r )7. — Camera outline. Wright's stain. Mouse 146, 111 liours. Male. 

 There is a large, irregular mass consisting of acidophil material which is 

 liberally provided with puhctiform basophil granules, ami. in addition, a 

 number of sharply staining elongated granules. It is difficull to determine 



just where in the development of the male parasite a form like this belongs. 



Fig. 58. Camera outline. Delafield and acid fuchsin. Mouse 106, 9 hours. 



Male. The chromatin is in the form of minute basophil granules. There 



is a large irregular mass of these, and three rounded clusters near the 



periphery. 



Fig. 59. — Camera outline. Iron hematoxylin and acid fuchsin. Mouse 106, 

 9 hours. Male. The chromatin is aggregated into clusters of 6ne granules, 

 all of which are sharply basophil. Some of these clusters are wholly independ- 

 ent of one another; others are still united by strips of acidophil substance. 



Fig. til). -Camera outline. Iron hematoxylin and acid fuchsin. Mouse 179, 

 16j hours, int. —1. Male. The chromatin occurs as minute basophil granules, 

 either scattered or aggregated into clusters. A marked tendency toward 

 the assumption of a peripheral situation is to be noted. The remnant of 

 the linin network is omitted in the drawing. 



Fig. 61. — Camera outline. Iron hematoxylin and acid fuchsin. Mouse 179, 

 lti'. hours, int. —1. The chromatin is in the form of minute basophil granules 

 which occur in clusters, most of which are peripheral. The remnant of 

 the linin network is omitted from the drawing. 



Fig. 62. — Camera outline. Iron hematoxylin and acid fuchsin. Mouse 179, 

 I65 hours, int. —1. Male. This figure portrays much the same conditions 

 as are shown in fig. 61, but only an optical section of the parasite is shown. 

 The granular clusters are thus seen to be exclusively peripheral. 



Fig. 63. — Camera outline. Delafield and acid fuchsin. Mouse 120, 10t and 



17 hours. Form supposed to be a male. 



Fig. 64. — Free-hand sketch. Iron ha'matoxylin and acid fuchsin. Mouse 120, 

 IO5 and 17 hours. Supposed male. 



Fig. 65. — Camera outline. Iron haematoxylin and acid fuchsin. Mouse 106, 

 9 hours. Male. The chromatin occurs as clusters of minute granules. 



Fig. 66. — Camera outline. Wright's stain and eosin. Mouse 152, IS hours. 

 Male. Optical section. The chromatin is in the form of minute, intensely 

 basophil granules, aggregated in clusters that are arranged in a regular man- 

 ner around the periphery. 



P'ig. 67. — Camera outline. Wright's stain and eosin. Mouse 152, IS hours, 

 int. —2. Male. Optical section. The granular clusters, the forerunners of 

 the microgametes, are seen to be arranged in a regular manner around the 

 periphery. They are slightly more compact than in fig. 66. 



Fig. 68. — Camera outline. Wright's stain and eosin. Mouse 152, IS hours, 

 int. —2. Optical section. The clusters are becoming more and more solid. 



Fig. 69. — Camera outline. Iron hematoxylin and acid fuchsin. Mouse 106, 

 9 hours. The microgamete nuclei have still further solidified. It is worthy 

 of note that fig. 69, from a 9-hour mouse, represents later conditions than 

 fig. 68, an 18-hour stage. 



Fig. 70. — Camera outline. Iron haematoxylin and acid fuchsin. Mouse 106, 

 9 hours. Optical section. The microgamete nuclei have become round 

 solid balls. 



Fig. 71. — Camera outline. Iron hematoxylin and acid fuchsin. Mouse 100, 

 9 hours. Male. Condition intermediate between those shown in figs. 09 

 and 70. 



Plate V. — Fig. 72. — Camera outline. Wright's stain anil eosin. Mouse 152, 



18 hours, int. —2. Male. The solid nuclei are elongating to form the micro- 

 gametes. 



Fig. 73. — Camera outline. Wright's stain and eosin. Mouse 152, IS hours, 

 int. —2. The elongation continues. 



