MOODIE: MAZON CREEK, ILL., SHALES. 331 
pean Branchiosauria are the same as those which distinguish 
it from Branchiosaurus, to which it is closely allied. The nar- 
row, elongate eye, placed close to the edge of the skull, is a 
character not observed hitherto in the Branchiosauria. It re- 
calls the condition described by Credner for the young forms 
of Branchiosaurus amblystomus Cred? 
EHumicrerpeton parvum Moodie, 1910. 
(Plate 3, figs. 3 and 4; plate 4; plate 5, fig. 1; plate 6, figs. 1 and 2.) 
The specific characters are found in the anatomical details. 
The impression of the outline of the entire body is preserved 
in both animals, and in both are found impressions and molds 
of the alimentary tract which in the younger animal are re- 
markably complete and instructive. 
The impression of the larger animal, which is probably an 
adult, presents the following elements: the entire skull; both 
humeri; impressions of posterior and anterior ventral arma- 
ture; portions of the alimentary canal; one femur; portions of 
a fibula and tibia; and the entire impression of the tail, on 
which, as in Micrerpeton caudatum Moodie, there occur two 
definite dark lines, one beginning at the tip of the tail and run- 
ning obliquely along the tail to where the impression is broken 
at the anal region; the other beginning at a distance of four 
and one-half millimeters from the tip and running almost 
parallel with the median line. These two lines undoubtedly 
represent the lateral line system. 
The skull is especially noted for its shortness and the great 
posterior width, as well as for the almost entire absence of the 
tympanic notch. The pineal foramen is located on a line with 
the posterior border of the orbits. The eyes themselves are 
narrow and acuminate at each end, with a pronounced con- 
vexity inward and a flattening outward. They are located on 
the very border of the skull, but relatively further posterior 
than in Micrerpeton.. No sclerotic plates are evident. The 
median suture can be indistinctly observed running the entire 
length of the skull. The sutures bounding the outside of the 
frontals and the squamosals are partially evident but not sat- 
isfactorily preserved. The mandible is represented by a mold 
which in a wax impression shows short, stumpy teeth. 
Posterior to the skull, at a distance of one millimeter, there 
are two sharp impressions, which may represent the anterior 
3. Zeitschrift d. Deutsch. Geol. Gesellschaft, 1886, Th. VI, Taf. XVI, fig. 1, 
