TONGUE OF TEEAMELES NASUTA. 



II. Structures with Mechanical or Tactile 

 Functions. 



The papillae of peculiar type. — These papillae are very 

 numerous, thickly covering the upper surface of the tongue 

 in front of the circumvallate papillae, and certainly continuous 

 over the organ in front of the anterior limits of the piece in 

 my possession. 



They are smaller and more thickly placed anteriorly, and 

 here I counted thirty-four on a square mm. of surface. Pos- 

 teriorly there were only sixteen on the same area. These pa- 

 pillae appear to be closely related to the compound filiform 

 type of other animals, differing in the regular ring-like arrange- 

 ment and the number of the secondary papillae, and also in 

 certain points of minute structure. 



Their appearance when examined as opaque objects is given 

 in fig. 10 ( X 55*25), a and b ; a representing an anterior, b a 

 posterior papilla. The summit of each papilla is surrounded 

 by a ring of fine hair-like papillae, generally ten in number, 

 which sweep backwards, and must act very effectively in retain- 

 ing small insects. 



The hair-like papillae are longer and finer anteriorly, and 

 form a more complete ring ; but even here the ring is most 

 developed posteriorly in each papilla^ and tends to become in- 

 complete anteriorly with feebler secondary papillae. This 

 arrangement becomes gradually more marked posteriorly, until 

 around the circumvallate papillae the anterior part of each ring 

 finally disappears, while the posterior part becomes immensely 

 developed as a very thick, blunt, secondary papilla, with one 

 or two small ones on each side of it. (One of these depressed 

 forms of papilla is seen in vertical section in fig. 1, p.) Part 

 of this transition is seen in fig. 4. I believe that in front of 

 this piece of tongue the papillae are in a short distance sur- 

 mounted by a symmetrical ring of hair-like processes. The 

 same transition occurs from the centre to the side of the tongue, 

 but is far less marked. Here the fine processes bend ujjwards 



VOL, XXIII. NEW SEH. I' 



