. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology. 388 Bulletin Museum of Compdraiiie Zoology, Vol. 144, No. 5. Figure 18. A, lateral view of skull of the earliest identifiable captorhinid, MCZ 1483, from the middle of the Belle Plains Formation. Cheek region is expanded and posterior teeth have chisel-shaped tips. There is only a single row of marginal teeth. B, occiput of Captorhinus pattern, UC 1119, Wichita River, near Vernon Crossing, Clyde Formation. XlV-i- more than lialf was covered. These mea- sures are not meant to correspond strictly to functional imits, bu
. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology. 388 Bulletin Museum of Compdraiiie Zoology, Vol. 144, No. 5. Figure 18. A, lateral view of skull of the earliest identifiable captorhinid, MCZ 1483, from the middle of the Belle Plains Formation. Cheek region is expanded and posterior teeth have chisel-shaped tips. There is only a single row of marginal teeth. B, occiput of Captorhinus pattern, UC 1119, Wichita River, near Vernon Crossing, Clyde Formation. XlV-i- more than lialf was covered. These mea- sures are not meant to correspond strictly to functional imits, but sinipK' to give a stan- dard for discussing the relative size of the areas available for jaw musculature. In Protorothyris archeri, the subtemporal fencs- trae occup\' approximately 27 percent of the palatal surface, in Romeria primus .31 percent, Ronicria texaiia 33 percent, and Protocaptorhinus pricei 37 percent. Other measurements demonstrate a similar widen- ing of the lower jaws to accommodate a greater mass of the adductor musculature. These changes set the stage for a second, even more radical organization of the denti- tion which occurred in the origin of the Captorhinidae (see subsequent section). A further series of changes, occurring simultaneously with those noted in the lower jaw, are seen m the occiput. One, which has no immediately obvious struc- tural or functional ad\'antage, is the os- sification of the otic capsule. This structure is only questionably recognizable in the Pennsylvanian members of the group. In the exoccipital appears to have occupied some of the area later recognized as opisthotic. In Protorothyris the exoc- cipital is clearly recognized, but little is e\'ident of the opisthotic. In Romeria primus the medial and ventral portions of of the otic capsule are ossified, but the dor- sal and lateral areas were apparently carti- laginous. In Protocaptorhinus all of the me- dial part is ossified, but the distal ends stop short of the s
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