Testis Weights in Tilapia (Pisces: Cichlidae)

fauna of the American Southwest. Pap. Mich. Acad. Sci. 46:365-404. MOHSEN, T. 1961a. Sur la presence d'un organe copulateur interne, tres evolu6 chez Skiffia lermae (cyprinodonte, Goodeidae). Compt. Rend. Seanc. Acad. Sci. Univ. Dakar 252:33273329. 1961b. Sur le dimorphisme sexuel et la pr6sence d'un organe copulateur tres evolud chez le cyprinodonte Goodeidae Skiffia lermae Meek. Ann. Fac. Sci. Univ. Dakar 6:163-180. 1965. A new key character in males of the family Goodeidae (Cyprinodontiformes). Nature 205(4976):1127. REGAN, C. T. 1906-08. Pisces. In: Biologia Centrali-Americana. 8:1-203. ROMERO, H. 1967. Catalogo sistematico de los peces del alto Lerma con descripci6n de una nueva especie. An. Esc. Nac. Cienc. Biol. M6x. 14:47-80. TURNER, C. L. 1933. Viviparity superimposed upon ovo-viviparity in the Goodeidae, a family auna of the American Southwest. Pap. Mich. of cyprinodont teleost fishes of the Mexican plateau. J. Morphol. 55:207-251. 1946. A contribution to the taxonomy and zoogeography of the goodeid fishes. Occ. Pap. Mus. Zool., Univ. Mich. No. 495, 15 pp. , G. MENDOZA, AND R. REITER. 1962. Development and comparative morphology of he gonopodium of goodeid fishes. Proc. Iowa Acad. Sci. 69:571-586. WEST, R. C. 1964. Surface configuration and associated geology in Middle America. In: Handbook of Middle American Indians. R.