Fig. 2
From: Sperm collection in Black-legged Kittiwakes and characterization of sperm velocity and morphology
Pictures of spermatozoa (400× magnification and phase contrast 2) showing: normal sperm (a); a sperm with S-shaped head (b); a head-less sperm (c, d); a sperm with burst head (e); a double-headed sperm (f); a sperm with bended head (g); a sperm with no acrosome (h); a sperm with abnormally long acrosome (i); a sperm with 90°-angle midpiece (j); a double-flagellated sperm (k); a sperm with split flagellum (l); a sperm with broken flagellum (m); a sperm with 90°-angle flagellum (n); and a sperm with coiled flagellum (o)