On the (xustatory Organs of some Edentata. 339 



Gustatory Structures. 



The OircumvaUate Papillae. — The two papillae required the 

 aid of a powerful lens to reveal their presence. They are as usual 

 on the same transvei'se line, 1,7 mm. apart, and lie completely con- 

 cealed in deep and narrow trenches, their apices, which are inclined 

 inwards towards the median line, being slightly below the openings of 

 the latter. At a short distance above their bases (which are con- 

 stricted) the papillae measiu-e 0,23 mm. in diameter, their height being 

 0,6 mm, or nearly three times the transverse diameter. I do not think 

 it probable that the mouths of the trenches can be closed. The 

 arrangement of the muscles beneath the papillae suggests a possible 

 di^awing downwards of the entire region, but not of the papillae alone. 

 Glands of the serous type are sparingly scattered through the con- 

 nective tissue stroma underlying the papillae, and their ducts open 

 into the trenches at various levels. 



The taste -bulbs are restricted to the lower two-thirds of the 

 lateral area of the papillae. There may he seventeen or more tiers 

 of them. They were not clearly -enough defined for me to determine 

 the mean dimensions of the typical bulbs of this species. One which 

 I measured, and which was probably somewhat below the mean, was 

 0,030 mm in length and 0,018 mm in breadth. No lateral gustatory 

 organs were found on this piece of tongue. 



The circumvallate papillae of Dasypus peha resemble in the main 

 those of higher animals, while those of Chlamyphorus truncates ap- 

 proach quite closely the marsupial type, the resemblance between them 

 and the anterior papillae of Belkleus and Phalangista being very 

 marked. The papillae of Dasyjms viliosns appear to hold an inter- 

 mediate position, both types being represented, although more or less 

 modified. 



Amherst, Mass. U. S. A., 

 5. June, 1890. 



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