At least two and possibly five species in three families of bats have evolved the fish-eating habit. Two Asiatic species, Myotis macrotarsus and M . ( Rickettia ) pilosa are suspected of being fish-eaters simply because of their large feet and claws (Eisentraut, 1951; Allen, 1936). A third Asiatic bat, Megaderma lyra , has on two known occasions dropped remains of fish, together with frogs, mice and insects from night-roosting places, but its habits are unknown (Gudger, 1943). It may occupy an ecological niche similar to that of the large omnivorous Phyllostomus of the Neotropical region. The remaining two are New World species that are known to catch and eat fish and small aquatic crustaceans. First, Myotis ( Pizonyx ) vivesi , found only along the shores of Baja California and Sonora, apparently subsists almost completely on this diet; of many stomach dissections that have been made, only one has revealed insects, while all others have shown only fish and shrimps (Reeder and Norris, 1954; Burt, 1932). I have collected fecal pellets of Pizonyx from roosts on two islands just offshore from Guaymas, Sonora, and found it possible to separate them into two classes according to whether they contain primarily decapod chitin or fish scales, the former pellets being dark red, the latter black. A sample that was thus sorted proved to contain almost equal volumes of each type of pellet. Since there were very few mixed pellets, one can infer that the diet of this species is about 50 per cent fish, 50 per cent shrimp. Pizonyx has been observed fishing, but the exact way in which it catches fish is still in doubt. My attempts to induce captive Pizonyx to catch fish in the manner described below for Noctilio have been unsuccessful. Megaderma lyra and Myotis macrotarsus have feet only …