508 SIM GLOVES, WHOM SI GIOVGIN TES) 
been taken a very large number of the Microsauria. Among the 
most common are Tuditanus, Leptophractus, Colosteus, Osteoce- 
phalus, and Ptyonius. 
Tuditanus was rather small form with a short and broad head 
and the orbits located far forward. There seems to have been 
a lack of the dermal scutes on the ventral surface and their 
place was taken by three pectoral shields that exhibit a strong 
sculpture on the external face; they were the expanded clavicles 
and the interclavicle. The whole animal was about three to 
four inches long. 
Colosteus reached a length of a foot in some cases. The form 
was elongate with rather short legs. There were three pectoral 
plates as in Zuditanus as well as a well-developed armor of fine 
scutes. Whe teeth were not of equal ‘size, the anterior somes 
being much the larger. 
FPtyonius exhibits a very high degree of specialization. The 
body was long and serpentiform, and the limbs had entirely 
disappeared so that the animal had reached the same stage of 
development as the modern snakes. One very peculiar thing is 
to be noticed about this form; the distal edges of the transverse 
processes and neural-spines were fluted or folded so that they 
present a fan-like appearance. 
Leptophractus was by far the largest of the Ohio forms, hav- 
ing about the size of an alligator. Only portions of the skull 
are known but enough to show that the skull was rather elon- 
gate, and that the teeth had the dentine folded as in the true 
labyrinthodonts. Near the anterior end of the jaw there was a 
large canin'form tooth. 
Osteocephalus resembled in some respects Ptyonius. The body 
was long and snake-like, and the skull was very acuminate. The 
anterior pair of limbs were absent or rudimentary, and the pos- 
terior pair were very short. The three pectoral plates found in 
most of these forms were absent in this one, and their place 
was taken bya profusion of slender bony rods that ran obliquely 
inward and forward covering the whole ventral surface. There 
were no dermal scutes as in the other forms. 
