518 MOODIE. [Vor. XIX. 
Necturus (Fig. 6). The arrangement and disposition of the 
lines containing the sense organs is practically the same in the 
two forms. The median lateral line takes its origin from the 
extreme tip of the tail or rather it ends there, and is continued 
to the base where the impression is broken. The dorsal lateral 
line has its origin rather abruptly from the median line at a 
distance of six millimeters from the tip of the tail. The 
sense organs were undoubtedly located beneath specialized 
pigmented scales on the surface of the animal’s body as in 
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Fic. 5.—Detail of lateral line on impresion of the tail of Micrerpeton 
caudatum. d, dorsal lateral line; m, median lateral line; xxx, impressions 
of cartilaginous vertebre. X 4. 
Fic. 6—Outline of the larva of Necturus maculosus Raf., showing 
arrangement of lateral line organs. d, dorsal lateral line; m, median 
lateral line; v, ventral lateral line. After Platt. Enlarged. 
many of the modern fishes, e. g., the Holocephali, and to this 
pigment is due the preservation of the lines in a visible form. 
“The fact that the arrangement of the lines of the sense 
organs of Micrerpeton corresponds so exactly to the condition 
found in Necturus is of considerable interest. Necturus alone 
among the modern tailed Amphibia has the arrangement of 
the lateral lines above described for Micrerpeton. All other 
forms of the Caudata as also the larval forms of the Salientia 
have an arrangement of the lateral line system which is per- 
