84 BULLETIN OF THE 



each of the two individuals 19 mm. long, papillce were found on the 

 sides of the body, and on one of them a few on the head, besides in the 

 regions where they occur regularly In one of these the papilhe on 

 the right side of the body were distributed in what I regard as repre- 

 sentatives of nine of the transverse series described in Clevelandia. 

 The first and second series behind the pectorals were represented by one 

 papilla each ; the third and fourth, by three papillae each ; the fifth, 

 sixth, and seventh, by two each ; and the eighth and ninth, by one each. 

 The series were evidently segmentally arranged, though not all were 

 on consecutive segments ; thus between the third and fourth series were 

 two myotomic plates ; between the fourth and fifth, four plates ; between 

 the fifth and sixth, two plates ; between the sixth and seventh, one 

 plate ; and between the eighth and ninth, two plates. 



Figure 25, Plate IV., shows the arrangement of a group of papillae 

 on the right side of the head of this same individual. As seen by the 

 figure, seven of these papillae were much larger than the remaining 

 ones, and were situated on quite prominent ridges of the skin. 



Although the papillae have been diligently searched for on the sides 

 of the body of other specimens, they have been found on the two 

 small ones only. The question at once arises, Are the papillae absent 

 from the larger ones because they have degenerated and completely 

 disappeared during the life of the individual ] All the evidence I 

 have on this point is contained in the facts presented. That the 

 papillae have been found only on the two small specimens examined, 

 and that they have not been found on any of the numerous large ones, 

 certainly suggests very strongly an affirmative answer to the question. 

 It must be said, however, that a considerable percentage of my larger 

 specimens are not so well preserved but that the papillae may possibly 

 have been present in them and escaped detection. But some of them 

 are well preserved, and were the papillae present they would, I am sure, 

 have been found. 



That the sense papillae are less numerous on Typhlogobius than on 

 several, at least, of its near allies, is evident. The question may now 

 be asked. Is it not possible that, although there has been no compensa- 

 tion for the loss of sight by an increase in number of the tactile papillae, 

 such a compensation has been brought about by a higher development 

 of the individual papilla; themselves? So far as structural evidence 

 is concerned, this is certainly far from probable. Figures 23 and 24 

 (Plate IV.) show sections of two papillae of the inner mandibular series 

 of Typhlogobius ; and for the purpose of comparison a section of a 



