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bulletin: museum of comparative zoology. 



considered it identical witli the tenth bat listed by Azara from Argentine, notwith- 

 standing that GeofFroy, in applying the name, gave it to a bat larger than his 

 M. obsnurus. It is not unlikely that M. obscurus should rightly refer to this 

 smallest species of the genus, as its forearm corresponds closely in length to the 

 dimension given by Temmiuck (1 inch, 5 lines), although he may have confused 

 the two. However, as the original descriptions of both species contain nothing 

 that is clearly diagnostic, and as the length of head and body (60 mm.) given 

 by Geoffroy for his M. obscurus is obviously more nearly that of the bat that I 

 have referred above to that species, I follow Thomas in the use of the name cras- 

 sicaudatus for the smallest species (forearm, 36-39). Specimens from Villa Rica 



MEASUREMENTS OF MOLOSSUS CRASSICAUDATUS. 



and Paraguari, Paraguay, loaned me by the U. S. National Museum are very 

 differently colored from skins of J/, obscurus. They are nearly seal-brown, with 

 the basal half of the hairs sharply grayish-white, on both surfaces. Specimens 

 from St. Vincent and Sta. Lucia, Lesser Antilles, are somewhat darker, but this 

 difference is probably due in part to the method of making up the skin. All 

 agree in having a peculiar gloss to the fur, characteristic of certain other species 

 of the Molossidae. Although the forearm measurement is nearly as great as that 

 of M. obscurus, the present species is of strikingly smaller bulk, and the long 

 grayish bases to the hairs, especially of the shoulders and chest, give alcoholic 

 specimens a quite different appearance. The skull is smaller than that of M. 

 obscurus, and the sagittal crest is weakly developed, usually only a slight ridge. 



