280 Tuckerman — Gustatory Organs of Lepus Americanus. 



their base, and having an average depth of 0'30 mm . The fur- 

 rows are often partly filled with epithelium. The mucosa com- 

 posing the body of each fold is divided into three quite sym- 

 metrical secondary folds or lamellae. The primary or central 

 lamella is taller and slightly broader than the two lateral, and 

 at its upper part is frequently forked. The two secondary or 

 lateral lamellae contain the taste-bulbs. A thin stratum of 

 stratified pavement epithelium is spread over the lamellae, but 

 is not sufficient to completely fill the depressions between 

 them. Serous glands are abundant in this region, and their 

 ducts, which are very numerous and occasionally of great 

 length, usually open at the bottom of the furrows. 



The taste-bulbs of this gustatory area are limited to the sides 

 of the folds and, in the main, are restricted to their upper half. 

 They traverse the epithelium more or less obliquely, and are 

 so close as to be in actual contact. They are disposed four to 

 seven tiers deep, the uppermost tier being on a level with the 

 top of the lateral wall, while the lowest is about opposite the 

 middle of the furrow. Each tier contains about thirty bulbs 

 in its entire length. If we allow for five tiers, we shall have 

 three hundred bulbs for each fold of the papilla. The bulbs 

 have a clearly-defined neck, and, when well developed, are 

 0'056 mm in length and 0-035 mm in breadth. 



The arrangement and distribution of the nerve-fibers in the 

 folds of the foliate organ is very similar to that which exists in 

 the circumvallate papilla. According to Drasch, who made 

 the lateral gustatory organ of the rabbit and European hare a 

 special study, there is beneath the basal membrane of the 

 lateral lamella a plexus formed of medullated nerve fibers. 

 From this plexus, fibers, corresponding in number to the sum 

 of the sensory cells, go directly to the bulbs. Other fibers, 

 more numerous, pass between the bulbs to the epithelium 

 situated above them. Many fibers, however, terminate in the 

 membranous stroma. Below the bulb region, in the entire 

 width of the lamella, is a connected stratum of ganglion cells 

 which contribute to the multiplication of the fibers. 



Other regions in which taste-bulbs occur, but which are not, 

 strictly speaking, exclusively taste areas, are the fungiform 

 papillae and parts of the epiglottis. In the fungiform papillae 

 of L. americanus bulbs are but sparingly present, and only 

 isolated ones were found in the epiglottis. 



