42 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 8o 



In the length of stride, which is equal to width of trackway, in size 

 of tracks, number of digits, and presence of a median groove, these 

 tracks bear a strikingly close resemblance to those of Batrachichnus 

 plainvillensis from the Carboniferous shales of Massachusetts. The 

 great width and depth of the median groove seem to indicate that it 

 was made by the dragging belly. The course is irregularly sinuous 

 and at one end the animal turned shari)ly to the left and with a more 

 moderate bend to the right, and where these bends were made the 

 median groove is much widened and smoothed out. (See pi. i8.) 



It is quite evident that the tracks were made by a salamandroid, 

 shortlegged crawling animal, which in moving about dragged the 

 belly. The foot structure also suggests its amphibian origin. No 

 other trails or tracks exactly comparable to it have been found at this 

 locality. 



From B. plainvillensis this species may be distinguished by the 

 shorter toes, their more forward direction, and the wider and deeper 

 median groove. It is distinguished at once from Dromillopus, also 

 a small form in these same deposits, by the greater number of toes 

 on the hindfoot. The specific name is suggested by the obscure con- 

 dition of most of the tracks. 



Genus DROMILLOPUS Matthew 



Dromillopus Matthew, G. F., Proc. Trans. Roy. Soc. Canada, Vol. lo, 

 1904, p. 91. 



Matthew characterizes the genus as follows : 



Generic characters. — 'Small digitigrade batrachians. Toes slender, directed 

 forward in a radial manner ; imprint showing only four toes to each foot. 



Genotype. — Droniillopiis quadriiidns Matthew. 

 This genus was established by Matthew on a series of small tracks 

 from the Carboniferous Coal Measures of Joggins, Nova Scotia. 



DROMILLOPUS PARVUS, new species 

 Plate 14 



Type. — Catalogue number 11,537, U. S. N. M. Consists of a small 

 slab of shale showing the trackway and tail drag of a small animal. 



Type locality. — About one-fourth mile west of the sign " Red 

 Top " on Hermit Trail near the head of Flermit Gorge, Grand Can- 

 yon National Park, x\rizona. 



Geological occurrence. — Hermit shale (about 40 feet above 

 Hermit-Supai contact), Permian. 



