No. 2.] LATERAL LINE IN EXTINCT AMPHIBIA. 533 
Great Britain has been figured and described by Atthey (19). 
In regard to the lateral line canals he says: “The mucous- 
grooves are two pairs. The anterior pair run backwards and 
inwards along the inner side of the naso-lachrymal suture 
as far as the posterior margin of the nasals; the posterior are 
deeper, and appear in two disconnected portions along the 
outer margins of the jugal and quadratojugal bones. The 
anterior pair of grooves are less deep and less distinct than 
those of Loxomma; the posterior are deeper, wider and 
rougher than those of that labyrinthodont.”” The skull studied 
by Atthey was in rather poor state of preservation, but it 1s 
evident that he detected the anterior portions of the supra- 
orbital canals and the jugal canal on one side, with possibly 
a portion of the infra-orbital. .He does not indicate the 
“mucous-grooves” on his drawing of the skull. 
The skull of Loxomma allmanni Huxley (20) is of pecu- 
liar interest in connection with the study of the lateral line 
system of the extinct Amphibia on account of the presence of 
a distinct anterior commissure which extends, clearly marked, 
according to the figure given by Embleton and Atthey 
(20), between the anterior extremities of the supraorbital 
canals. The antorbital commissure is also clearly preserved. 
The occipital cross-commissure is not represented in the draw- 
ing of Embleton and Atthey nor in that given by Miall (21). 
Miall’s representation of the canals of Loxomma is manifestly 
inaccurate in regard to the antorbital commissure. In the 
skull of Gonioglyptus, Huxley (22) has figured the lateral 
line canals as more strongly developed than usual. Unfortu- 
nately only fragments of the skull remain. Huxley’s restor- 
ation of the lateral line canals in this form is, so far as I can 
learn, conjectural. The manner in which the supraorbital 
canals curl around the nostril, if such is their normal course 
in Gonioglyptus, is without parallel among the other laby- 
rinthodonts. 
One of the main points to be brought out in this discussion 
of the lateral line canals of the extinct Amphibia is the cor- 
relation of the cranial elements with those of the fishes so 
