No. 470] 



HABITS OF NECTURUS 



125 



tint. The mottling is due to the presence of large irregular dark 

 areas which are surrounded by a pale yellow margin. Often 

 these spots coalesce to form larger areas or hands. In the vounger 

 animals there is frequently a dark band extending from the nostril 

 to the eye, from the eye to the anterior margin of the gills, and 

 from the posterior margin of the gills backward along the side 

 of the body. In some cases the upper surface presents no large 

 areas but is more uniform, and the chromatophores and lipo- 

 chromes are so distributed that the surface presents a granular 

 appearance. The ventral surface of the body frequently becomes 

 lighter toward the median line and in some a sharply defined 

 linea alba is present. The lower part of the head and tail are 

 frequently dotted with small clusters of lipochromes. 



In short, the contrast of black and yellow may in some appear 

 vivid, in others subdued and again disappear almost entirely. 

 It is probable that these variations in color are responsible for 

 a number of specific names. As 'an instance I might state that 

 some years ago Dr. Garnier ('88) described a small Necturus, 

 taken from the Maitland and Lucknow Rivers in Ontario, to 

 which he gave the name Mcnohranchus lateralis, var. latastei. 

 "The colouration above was black, the abdomen sooty and the 

 gular fold white." 



During the summer of 1904 the writer was fortunate enough 

 to secure tw o young animals which measured about 4 and 6 inches 

 respectively. The smaller corresponds closely to the description 

 given by Dr. Garnier and there is every reason for l)elieving that 

 the animal in question is the young of Xfcfiinis marulosm. The 

 older of the two presents the general coloration of tlie adnlt. That 

 Necturus should undergo such striking chiinges in color may 

 appear remarkable to one who has not studied the earlv stages 

 but when one has followed tlic changes in color pattern- dunng 

 growth he finds that they are no less striking and reniarkahle 

 than in the birds. 



//a/;/7a/.-The environment to which they are be.t adapted 

 is not known. In spriiig and siiinmer excepting th.e time of egg- 

 four to eight feet deep where a clean sandy bottom is fairly well 

 covered by vegetation. In the autumn they are found m pairs 



