MOODIE: MAZON CREEK, ILL., SHALES. 343 
MEASUREMENTS OF THE TYPE OF MAZONERPETON COSTATUM MoopIRE. 
nm, 
Length of portion of skull preserved............. 14 
Teno cheoLerichinclavicle taste cea aac 16 
Wadthiofsrichtclavicles-tiaasecerer errno ceiass ee 4 
Length of dorsal region represented.............. 30 
Gene thoficenvicalenibnrmmea acts eae talon aa 8 
senothsotsdorsaliGribmacm-rccimec cere Genie: 6.5 
Length of caudal rib..... epoictss Ses ts Shskareiate Aus negsiagaene 3 
Length of caudal portion of the body preserved... 55 
Menothwotemandiblewwerrsac seme case otic coos 15 
Greatestiwadthy ceria cisions micielcerrave/. alee etaeie sais 6 
ene theo teriob eh equssicrrsiesteerine ecinees cele icinis 10 
Greatest width of right humerus................. 2 
The type is No. 800 (777) of the Yale University Museum. 
Collected at Mazon Creek, Grundy county, Illinois. 
MEASUREMENTS OF SPECIMEN No. 804 (332). 
mm, 
Gen gth jofpribyy. was neces ceysie ein ewsictas tons cle Oatasewe 11 
Widthe otmheadwoliri pm mete merrier atte a arc ae 2 
Diametersol Shattetrpacoccteccrncisn croc ieee iL 
Amphibamus grandiceps Cope, 1865. 
(Plate 1, figs. 1 and 2; plate 5, fig. 3; plate 7, fig. 1; plates 11, 12, 13.) 
The collection of Carboniferous Amphibia loaned the writer 
for study by the Yale Museum contains an unusually perfect 
example of Amphibamus grandiceps Cope. The skull is nearly 
complete, although the sutures are indistinct. The following 
parts have been identified in the specimen: the greater part 
of the vertebral column, ventral armature, ribs, portions of 
the pectoral girdle, the pelvic girdle, and all four limbs, with 
the hands and feet in an unusually perfect condition, all very 
clearly and distinctly shown on a nodule from the Mazon 
Cheek shales of Illinois. The specimen was collected near 
Morris, Illinois, in 1870. 
The writer (1909) published a restoration of this species, 
in which he gave to the vertebral column twenty-six verte- 
bree, the exact number being at that time uncertain. Professor 
Cope (1865) in his original description gave the number as 
thirteen between the interscapular region and the sacrum. 
Hay (1900) thought the number was less than twenty. The 
present specimen shows that there were twenty-two in the 
presacral region, not including the sacral vertebra; thus show- 
ing that in two cases too few vertebre and in the third case 
too many vertebree were assigned to the vertebral column. 
