158 BULLETIN OF THE 



endotuvbinal plate is free beneath, and possesses a broad fleshy lobe 

 directed forward. The fourth plate, unlike the preceding, is not free at 

 its base beneath, and is the smallest of the series. It presents a concave 

 border in front, and is furnished with a fleshy lobe which is directed 

 backward. The surfaces of all the olfactory plates are separated by 

 appreciable intervals. 



Artibeus (Plate V. figs. 4, 6). — The pai-ts in this genus closely resem- 

 ble those of Pteroderma. The ectoturbinal is exceeding slender, and is 

 furnished with a fleshy summit, which is convolute outward. Its upper 

 portion alone is seen from the median surface. The first endoturbinal is 

 free below, but fleshy above. It is produced forward one half its length 

 beyond the end of the ectoturbinal in the form of a lobule, is acumi- 

 nate, and possesses as in Dermanura a small posterior lobe. The second 

 endoturbinal is concealed by the third. "When the latter is pressed aside 

 at its upper part the small biconvolute plate of the second plate is seen 

 in position. The third endoturbinal possesses a large lobule, which lies 

 upon the median surface. The lobule is subrounded in form, com- 

 pletely occupying the upper edge of the plate, so that it appears to arise 

 from the cribriform plate by a pedicle. The fourth endoturbinal pre- 

 sents an exposed plate on the median surface. It is beneath the convex 

 non-perforate space, and yields a single large convolution, which is turned 

 outward. Although this plate lies back of the cribriform plate, the 

 absence of any connection between it and the vomer would seem to 

 show that the arrangement met with in many mammals is departed 

 from. 



Dermanura. — In this genus the ectoturbinal is inflated, and is pro- 

 jected beyond the first endoturbinal one half its length. The first 

 endoturbinal is concave outward, is without a lobule, and in a measure 

 embraces the last-named plate. The remaining plates are arranged as in 

 Pteroderma. On the encranial surface the depression for the main plate 

 is without associated foramina, but in their stead three openings are 

 seen, ranged transversely. The ectoturbinal opening is single. 



The Physiological Anatomy of tiie Olfactory Sense in the 



Mammalia. 



The olfactory organ in the mammalia is an appendage to the respira- 

 tory tract. It depends upon the direct contact of the odoriferous parti- 

 cle upon the specific cell fixed upon the olfactory surface and united 

 with a terminal filament of an olfactory nerve. The olfactory plates 

 upon which the cells lie are composed of two sets, an ectoturbinal and 



