580 



Bulletin American Museum of Natural History. [Vol. XXIV, 



in size between the two parts, but the portion representing the first molar 



rises much higher than in the nor- 

 mal tooth, the two cusps of the 

 fuse<d teeth being of equal height 

 on the right side and nearly so on 

 the left. The accompanying illus- 

 trations render further description 

 unnecessary. 



The specimen showing the ab- 

 normality is quite young, the milk 

 incisors being still present, but the 



Fig. 2. Artibeus quadnvMatus, No. 24381. rest f the teeth Were fu % devel - 



sp U edmenT ie l of dght u PP er tooth row - normal oped, except the canines, which 



had not quite reached their full 

 height. While this anomaly may not have much significance in its bearing 



Fig. 3. 



Fig. 4. 



Artibeus quadrivittaius, No. 24398. Inside view of left upper tooth row, showing 

 fused premolars. ^. 



Fig 4. Artibeus quadrivittatus, No. 24381. Inside view of right upper tooth row, normal 



Fig. 3 

 specmen, f. 



upon the 'concrescence theory' of the formation of cusps, it is of considera- 

 ble interest on account of the extreme rarity of its occurrence. 



II. BATS FROM THE ISLAND SAN DOMINGO. 



A small collection of bats, made by Mr. A. H. Verrill in January, 1907, 

 during his expedition to San Domingo in 1906-1907, have been recently 

 acquired by this Museum. They number only six species, but have con- 

 siderable interest, since little has hitherto been definitely known regarding 

 the bats of San Domingo. Two of the species appear to be undescribed. 



The only other mammals obtained by Mr. Verrill on the island are 



