Abstract

AN ‘accessory’ processus muscularis, the significance of which has not been disclosed, was described by Doran1 in the malleus of Asellia tridens (Microchiroptera). The process is said to be of very rare occurrence in bats. Dissection of fresh Asellia tridens, however, revealed the presence of a two-headed tensor tympani muscle, the short and smaller outer head being inserted to the ‘accessory’ process, while the long inner head is attached to another process which Doran considers as the homologue of the processus muscularis constantly observed in other insectivorous bats. This remarkable feature of the tensor tympani to which I can find no reference in the literature is not a peculiarity of Asellia tridens (Hipposideridæ) alone, but is found in various other species of bats. It occurs in Taphozous per-foratus, Liponycteris nudiventris and Rhinopoma microphyllum (Emballonuridæ), in Tadarida ægyptiacus and T. teniotis (Molossidæ).

References

1. Doran, A. H. G., Trans. Linn. Soc., London, 1 (1878).
2. Edgeworth, F. H., Quart. J. Micr. Sci., 59 (1914).