512 MOODIE. [VoLt. XIX. 
Parker ascertained that the lateral line organs in some of the 
fishes seemed to respond to slow wave vibrations. It is thus 
through the action of wave vibrations on the external lateral 
line organs that the animal is notified of a disturbance in the 
water near it, the wave vibrations of which were too slow to 
affect the organs of touch or hearing. 
It is not our purpose to discuss here the functions of these 
organs, but to describe the manner of their occurrence in the 
ancient Amphibia, on the crania of which the canals are often 
clearly marked. Unfortunately there are but comparatively 
few skulls in existence and they are scattered far and wide 
in the museums of the world. The remains of the early 
Amphibia are represented in great part by fragments. 
Occasionally, however, a good skull is discovered and almost 
always the lateral line canals are well shown on such skulls. 
But there is another source of grievance. When such good 
skulls are described, the describer of the specimen either pays 
but scanty attention to the subject of the lateral line system, 
or omits a discussion of it altogether or describes the canals 
inadequately. We are indebted to the paleontologists of the 
world for the knowledge we have of the lateral line canals 
of the ancient Amphibia and more especially to von Meyer and 
Fraas. 
The lateral line system, as preserved in the extinct Amphibia, 
is of a very peculiar character and is unlike anything with 
which I am acquainted among the fishes, although some degree 
of correlation is possible. The entire set of structures on the 
skull of the Stegocephala is usually spoken of as the lyre or 
lyra, the former being the more correct term. The system 
of organs is represented by canals of various forms and with 
varying directions. They are usually in the form of gutters 
with more or less vertical sides, although sometimes, espe- 
cially among the Microsauria, the canal is represented by a 
row of elongate pits. The bottoms of the well-formed canals 
may be smooth or roughened by pits such as commonly occur 
in the crania of the Stegocephala. The smoothness of the 
bottoms of the canals is, I think, an indication either of age 
