Fig. 29 in New Taxa And Cryptic Species Of Neotropical Snakes (Xenodontinae), With Commentary On Hemipenes As Generic And Specific Characters

Fig. 29. The African genus Prosymna includes examples of extreme hemipenial diversity. A. Prosymna ambigua bocagii Boulenger, a snake with a slender, single (unforked) hemipenis longer than the tail when everted. Drawing of AMNH R-12145, reproduced from Schmidt (1923: 89). B. Same specimen as above, with tail opened, showing complex ''accordion'' folding of the uneverted contralateral hemipenis. The retractor muscles originate threadlike at the very tip of the tail, both with a small Z-shaped fold toward the hemipenis. Notice at the bottom side that the everted right hemipenis has the tip broken off. Inset at top: Greatly enlarged view of the folded part of the inverted hemipenis. Inset at lower right: Enlarged view of the tip of the broken right hemipenis, showing ridgelike structures at the terminus. C. Prosymna sundevallii (A. Smith) hemipenes showing peculiar anastomosing flouncing, from Broadley (1980: pl. IIA). Abbreviations: AG, presumed small anal gland; HP, hemipenis; Mus, termini of left and right retractor muscles; MusZ, large Z-shaped fold in left retractor muscle; SS, sulcus spermaticus.