. Report of the Geological Survey of Ohio. Geology; Paleontology; Mines and mineral resources; Zoology; Paleobotany; Botany. Such are the characters of a genus whose affinities are interesting but somewhat obscure. The hyoid apparatus is better developed than in any other here described, but it is by no means certain that it was branchiferous at maturity; nor does this character, on the other hand, render it certain that the animal is the larva of one of the other forms here described. The well ossified ribs and vertebrae are favorable, though not conclusive, evidence for adult age, while the
. Report of the Geological Survey of Ohio. Geology; Paleontology; Mines and mineral resources; Zoology; Paleobotany; Botany. Such are the characters of a genus whose affinities are interesting but somewhat obscure. The hyoid apparatus is better developed than in any other here described, but it is by no means certain that it was branchiferous at maturity; nor does this character, on the other hand, render it certain that the animal is the larva of one of the other forms here described. The well ossified ribs and vertebrae are favorable, though not conclusive, evidence for adult age, while the structure of the hyoid apparatus is more like that of the gilless genera Amphiuma and Protonopsis than it is like the branchiferous genera Siren and Necturus, or the branchiate young of salamanders. Thus it differs from Proteus in the presence of the first axialhyal and the two first basihyals, and from this genus and Necturus in the possession of four dis- tinct pleural branchihyals. In this it agrees with Amphiuma, as it does also with Protonopsis, in the three haemal branchihyals.* Siren has only two of these elements, the first and second, without the uiaryionD; 'c axialhyal; h', basal third. As a consequence, in Siren the third and iiyai,A",ceratoiiyai;A"', ?sty ^ lohyal; fru, hsemalbranchihyal; fourth pleural elements have no corresponding hse- *'. ^'. 6'". *"'", pleural toanchi- mal support, an arrangement totally different from that of Cocytinus. The arrangement in larval Amblystoma and Triton is quite similar to that in Siren, excepting that in Triton the small basi- hyals are present. The question as to whether this genus was in life branchiferous or not is not easily de- cided, since the hyoid apparatus is about equally developed in the branchiferous gen- era Siren and Necturus, and the air-breathers Amphiuma and Protonopsis. Some considera- tions, however, point to an air-breathing type like the last two, though the individual may poss
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