In van der Hoeven’s Tijdschrift voor Natuurlijke Geschiedenis en Physiologie, 1838-39, a small bat has been described by Dr. S. Müller under the name Pachysoma brachyotis. That author collected a large number of specimens, all in the same locality, a deep lime-stone cave, on the bank of the river Dewej, in the interior of Borneo: these type specimens are in our Museum. Dobson (Catalogue, 1876) remarks under the head Cynopterus brachyotus that an examination of the types of brachyotus (lege brachyotis) in the Leyden Museum has shown him that the Andaman-island variety (described by him in 1873 as Cynopterus marginatus, var. andamanensis) is identical with Müller’s species. In the well-known Catalogue published by Dobson in 1878, no word however, concerning this species; Cynopterus brachyotis Müller seems to be entirely overlooked by that author. I am not aware that the species has been recorded or mentioned after the year 1876, neither in the P. Z. S. nor in any other periodical, so that I fear that it is on the way to disappear among its fellows; the more as Dobson has bestowed the specific title of brachyotis upon a new species of the with Cynopterus so closely allied family Cynonycteris (see P. Z. S. 1877 and Catalogue, 1878) and so one perhaps might confound them and believe that Müller’s brachyotis same as Dobson’s brachyotis, would be the meanwhile they represent two well defined and really very different species, belonging to two distinct families.