Fig. 27. Spermatozoon. Pear shaped head. × 670. Fig. 28. Spermatozoon. The head is quite long, and pointed at its posterior end. × 670. Fig. 29. Spermatozoon, showing a constriction at middle of the head. × 670. PLATE XII. Fig. 30. Microcephalic spermatozoon. × 670. Fig. 31. Spermatozoon. The head is small, and pear shaped. × 670. Fig. 32. Macrocephalic sperm. The middle piece is much thickened. × 670. Fig. 33. Tailless spermatozoa. × 670. [Illustration: PLATE I] [Illustration: PLATE II] [Illustration: PLATE III] [Illustration: PLATE IV] [Illustration: PLATE V] [Illustration: PLATE VI] [Illustration: PLATE VII] [Illustration: PLATE VIII] [Illustration: PLATE IX] [Illustration: PLATE X] [Illustration: PLATE XI] [Illustration: PLATE XII] ------------------------------------------------------------------------ TRANSCRIBER’S NOTES Page Changed from Changed to 54 [blank] Bacteriology of the Genital Tracts of Mature Infertile or Sterile Bulls Group VI ● Typos fixed; non-standard spelling and dialect retained. ● Enclosed italics font in _underscores_.