[Mesocestoides leptothylacus n. sp. and the problem of nomenclature in the genus Mesocestoides Vaillant, 1863 (Cestoda, Mesocestoididae) (author's transl)].

M. leptothylacus n. sp., a common parasite of the Red Fox (Vulpes vulpes) in Southwest Germany, is characterized by a slender elongated cirrus pouch containing a cirrus with only one loose convolution and by approximately 90 testes surrounding the other genital organs completely, quite a number of them lying outside the lateral excretory canals.--The decision for a new name arised from the following considerations: 1. Goeze (1782) described Taenia lineata with characteristics of the genus only. 2. There is no type material left by Goeze. 3. None of the later authors could know which species was meant by T. lineata. 4. None of the later descriptions was exact enough to adjoin it to the old name today. 5. All descriptions under the name of M. lineatus have to be revised. Certkova & Kosupko (1795) in order to preserve the well known name assigned to it a completely new species but did not select a neotype nor did they choose a species from the terra typica; thus the name of that species has to be altered. 7. Goeze in the same book in which he described M. lineatus gave a very superficial account of a cestode presumed to be a variation of a Taenia cateniformis which probably was a Mesocestoides, too. The specimens apparently were not gravid so that the author neither recognized the relationship to his T. lineata nor could he be sure about a possible identity of the two. 8. Thus, the name assigned to this second description, M. literatus (Batsch, 1786) is a nomen dubium.