Studies in Spermatogenesis Volume Ii Part 5

PLATE X.

_Odontota dorsalis._

FIGS. 69-70. First spermatocyte, metaphase.

71. First spermatocyte, equatorial plate.

72. First spermatocyte, metaphase, showing metakinesis of the heterochromosomes.

73-74. First spermatocyte, anaphase.

75-76. Second spermatocyte, equatorial plates.

77. Second spermatocyte, showing metakinesis of the small chromosome (_s_).

78. Second spermatocyte, prophase, showing chromosomes longitudinally split.

79-80. Young spermatids, _n_ the chromatin nucleolus.

81-87. A series of stages in the development of the sperm head, showing the various phases in the history of the chromatin nucleolus (_n_).

88. Cross-sections of nearly mature sperm heads.

89-90. Equatorial plates of spermatogonia of abnormal individual, 15 large chromosomes, 2 small ones.

91. First spermatocyte from same testis, spireme stage, showing 2 small chromosomes a.s.sociated with 1 large one and a plasmosome.

92. First spermatocyte from the same testis, metaphase showing a similar heterochromosome group.

93. Second spermatocyte from same testis, equatorial plate, showing 2 small chromosomes.

_Epilachna borealis_ (_Family Coccinellidae_).

94. Equatorial plate of spermatogonium, 17 large chromosomes and 1 small one.

95. First spermatocyte, spireme stage, showing the unequal pair.

96-97. First spermatocyte, late prophases.

98. First spermatocyte, metaphase, showing chromosomes of different forms.

99-100. First spermatocyte, equatorial plate.

101. Unequal heterochromosome pair from a metaphase.

102. First spermatocyte, anaphase; ordinary chromosomes stippled to show more clearly the metakinesis of the unequal pair.

103. Second spermatocyte, equatorial plates.

104. Second spermatocyte, prophase.

105-106. Abnormal giant spermatids, probably in process of degeneration.

_Euphoria inda_ (_Family Scarabaeidae_).

107. Equatorial plate of spermatogonium, 20 chromosomes. The 2 smallest are the unequal pair of heterochromosomes (_l_ and _s_).

108. Resting spermatogonium, showing plasmosome (_p_).

109. First spermatocyte, spireme stage.

[Ill.u.s.tration: STEVENS PLATE X.

N. M. S. del.

COLEOPTERA]

PLATE XI.

_Euphoria inda._

FIGS. 110-111. First spermatocyte, prophases.

112-113. First spermatocyte, late prophase.

114-116. First spermatocyte, metaphase.

117. First spermatocyte, equatorial plate, _x_ the unequal pair.

118-120. First spermatocyte, anaphase.

121. First spermatocyte, daughter plates.

122. Second spermatocyte, prophase.

123. Second spermatocyte, equatorial plates.

124-125. Second spermatocyte, daughter plates of the two cla.s.ses.

126-127. Second spermatocyte, anaphase.

128-130. Spermatids, _n_ the chromatin nucleolus.