228 



C. H. EIGEXMAXN AND C. KENNEDY, 



the specimen suggested that 

 the inhibitory force which kept 

 these color cells from spread- 

 ing, or the positive tropism 

 which kept them together, was 

 dissolved and the cells scat- 

 tered evenly in a single layer 

 over the surrounding region. 

 The centers of distribution are 

 still distinguishable as darker 

 areas at the margin of or in 

 the blotches. In the nape, 

 for instance, four spots that 

 were in part responsible for 

 the blotch are seen at its four 

 corners. It is very probable 

 that color cells in addition to 

 those originally forming the 

 spots are concerned in forming 

 the blotches. 



2. A specimen of Pygidinui 

 riviilatiun, 195 mm. long, a 



catfish from Lake Titicaca, has 

 on the left side, in the place 

 of the normal maxillary bar- 

 bel, one which is dichotom- 

 ously branched near its base 

 into a dorsal and ventral 

 branch. The dorsal branch 

 is evidently the normal barbel, 

 the ventral being the adventi- 

 tious one. The ventral branch 

 is but slightly shorter than 

 the dorsal branch which is 

 itself a little shorter than its 

 fellow of the right side. 



3. A specimen of Xiplior- 

 Jiainpluts jcuvnsii, 155 mm. 



r; 



