No. I.] OBSERVATIONS ON THE GUSTATORY ORGANS. 73 



lated nerve-fibres (and what appear to be isolated ganglion cells) 

 are scattered through the intra-papillary stroma. The bulbs are 

 disposed on the lateral area, sometimes nearly filling it. The 

 number of tiers is about twenty, the mean number of bulbs in 

 a tier being ninety. The bulbs are closely set, and measure 

 0.058 mm. in length and 0.030 mm. in breadth. A few scattered 

 bulbs are present in the epithelium of the outer wall of the 

 trench. 



The Lateral Gustatory Organs. — These organs are simple in 

 construction. Each consists of a single complete fold of the 

 mucous membrane, bearing bulbs on its upper surface and on 

 one of its lateral slopes. The fold measures 0.35 mm. trans- 

 versely, and is 0.40 mm. in height. Serous glands are present, 

 and penetrate deeply the muscular layer of the tongue. Their 

 ducts, which are very plentiful, open into the furrows at differ- 

 ent levels. It is evident here, I think, that the furrows have 

 developed first from simple gland-ducts, and hence are primary, 

 the folds being secondary. This accords with the view advanced 

 by Poulton, as touching the lateral organ of Marsupialia. The 

 organs are supplied with non-medullated nerves, and groups of 

 ganglion cells are present in the axial portion of the folds. The 

 bulbs measure 0.054 mm. in length and 0.030 mm. in breadth. 

 A second but partly differentiated fold, adjacent to the bulb- 

 bearing slope of the complete fold, is traversed by gland-ducts 

 and well filled with bulbs. 



In structure the fungiform papillae are of the usual mammalian 

 type, and are richly supplied with nerves. The bulbs are equal 

 in size to any observed in the circumvallate papillae, although 

 they have fewer sensory cells. The compound filiform papillae 

 follow in the main the type observed in D. villosiis. 



The Tongue of Miis dccnniamis. 



General Description. — The organ shows two well-marked 

 divisions, a more or less expanded anterior portion and an 

 elevated posterior part. The anterior division is 16 mm. in 

 length, 9 mm. in breadth, and is free from the floor of the mouth 

 for 12 mm. The upper surface and sides of this division are 

 covered with closely set, recurved filiform papillae. A well- 

 defined median groove, 8 mm. long, passes through the tip of 



