Fig. 4. The Type of Micrerpeton caudatum Moodie from the Carboniferous of Mazon Creek, Illinois. In the collection of the University of Chicago. Twice natural size.
known to us. It is peculiar in the wide horn-like expansions of the skull (Fig. 5). There is no pineal foramen in the dorsum of the skull and it lacks a few of the characters of the other amphibians known from this region.
Interest in the early Amphibia has not slackened in the later years and there have been many contributors to the knowledge of the early forms. There are at present nearly seventy-five species of Carboniferous Amphibia known from North America and as many have been recorded from the Carboniferous and Permian of Europe; many more undoubtedly await discovery. The forms do not differ greatly in their structure in the two continents and each has relatively the same amphibian fauna, although the North American fauna is perhaps somewhat older than the European one. Certainly the Branchiosauria are found
Fig. 5. A Skull of Diplocaulus magnicornis Cope from the Permian of Texas. In the collection of the University of Chicago. Three tenths natural size.