LATERAL LINE SYSTEM IN EXTINCT AMPHIBIA 319 
portance of the lateral line canals in vertebrate morphology it is 
thought worth while to copy a few of Wiman’s figures and attempt 
to correlate the lateral line canals in these new forms with the 
work which has previously been done. 
The canals as they occur on the skull of Lyrocephalus euri 
Wiman (fig. 1) are broad but perfectly distinct grooves which 
have the arrangement indicated in figure 1. By ‘Nasofrontal- 
kaniile’ I presume Wiman means the supraorbital (fig. 1, So). 
He says that this canal varies in different individuals so that some 
specimens exhibit the canal twice the breadth of others. Wiman 
remarks further that ‘‘Der Verlauf der Schleimkaniéle ist wie 
iiberhaupt bei wenigstens den héheren Stegocephalen auffallend 
konstant”’ but there are certain very interesting deviations from 
the usual condition. There is to be noted in the figures an 
asymmetrical arrangement of the canals in all of the forms 
figured. This asymmetry is especially apparent in the temporal 
region. 
The supraorbital canal (figs. 1, 2, 4, So) has a course running 
nearly the entire length of the skull; and at the posterior pro- 
jection (fig. 1, X) the canal was probably elevated into the skin 
and made no impression on the skull bones. On the post-orbital 
bone the supra-orbital canal is joined by a branch from the 
temporal and jugal which may be looked upon as an extension 
of the hyomandibular canal which in turn runs down on to the 
mandible as the homologue of the operculo-mandibular of Amia 
(Allis ’89). There are various anomalies associated with the 
supraorbital canals. In one skull (Wiman 714, pl. 1, fig. 1) 
the canals end abruptly at some distance from the ascending 
hyomandibular. On another skull the temporal canal fails to 
join the supraorbital canal. Yet again the canal of one side may 
join the ascending branch and on the other be present in the 
form of a very slight groove or represented by a row of pits 
(fig. 4) which doubtless contained the sensory organs. 
The ‘Tremalkaniile’ of Wiman are the canals which have been 
termed temporal (Moodie ’08, p. 514, fig. 1) and probably 
represent a backward extension of the hyomandibular or else 
a new formation in the Amphibia. The occurrence of the tem- 
