MUSEUM OF COMPARATIVE ZOOLOGY. 81 



distribution of the papilla3 of Typhlogobius are shown, except for a few 

 scattering ones to be spoken of shortly, in Plate I. Figure 3, jmp. 



There are two series near the edge of each side of the lower jaw, 

 running parallel with it. The series of one side do not quite unite, 

 anteriorly, with those of the opposite side, the interval between their 

 ends being occupied by a slight prominence in the epidermis. Posteriorly 

 the scries extend beyond the angle of the moutli and turn upward some- 

 what to terminate about on a level with the mouth opening; the rows 

 nearer the median line, however, extending slightly farther than the 

 ones nearer the edges of the jaws (Fig. 3). The papilhe of the inner 

 series are considerably larger than those of the outer series, there 

 being about six of the former to thirteen of the latter. The larger 

 ones are on the average about 0.08 mm. in diameter, though the size 

 varies considerably. The papillae of the outer series are situated on a 

 quite prominent ridge, while the inner ones are, on the contrary, in a 

 shallow furrow. These ridges and furrows are, however, apparently 

 a part of the longitudinal foldings in the integument that are charac- 

 teristic of this region of the head, rather than structures expressly for 

 the accommodation of the sense buds. Another series of papillae is 

 found on each side of the head above the mouth, and having very 

 nearly the same direction as those below, though inclining toward 

 the latter somewhat in their course backward. These extend anteri- 

 orly to near the tips of the fleshy knobs shown at f. Figure 1. The 

 papilla} above the mouth are of about the same size as the smaller ones 

 on the lower jaw. Still another series is found on each side of the 

 head on the operculum, extending however at a right angle, or nearly 

 so, to the series already described (Fig. 3). These are also of the 

 smaller variety. The number in both this and the upper-jaw seines is. 

 more variable that in the lower-jaw series, though the transverse series 

 never extend far on to the top of the head. 



In Lepidogobius and Clevelandia both lower-jaw series are present, 

 and have precisely the same arrangement and form as in Typhlogobius ; 

 and in addition papillfe are numerously present on various parts of 

 the head and body where they do not occur in Typhlogobius. Thus 

 on the head of Lepidogobius there are at least several hundred in addi- 

 tion to the ones on the lower jaw. On each side of the head, beginning 

 at a point a little above the mouth and somewhat nearer its angle 

 than the end of the snout, four rows take their origin and diverge 

 irregularly. The row nearest the mouth bends downward somewhat as, 

 in its backward course, it reaches the angle of the mouth, and it extends, 



VOL. XXIV. NO. 3. 6 



