several other species of the Microsauria. It will be noticed that with the changed condition of the squamosal the temporal canal has changed also, and this is further proof of the close connection between the cranial elements and the lateral-line canals, as Allis has maintained for _Amia_. (See in this connection C. J. Herrick, Journ. Comp. Neurol., vol. II, p. 224, 1901.) The Diplocaulia, an amphibian order allied to the Branchiosauria (477) and through them to the Caudata, have the lateral-line system apparently well-developed. The skulls are always crushed flat, so that the canals are nearly obliterated. On the mandible, however, the canals are clearly distinct and apparently run the entire course around the mandibular rami. On a well-preserved skull of _Diplocaulus magnicornis_ Cope there are indications of three lateral-line canals (477, pl. 1). The infraorbital is clearly marked as a well-defined groove just below the orbit. The supraorbital is indicated only for a short distance, and there are indications of the temporal canal. The operculo-mandibular canal has its course, for the most part, near the middle of the rami, but as it approaches the posterior angle of the mandible it suddenly changes its course and drops down to the lower edge, only to rise again and to come out strongly marked near the median plane on the posterior angle of the mandible. The Temnospondylia, as represented by _Eryops_, _Cricotus_, and _Archegosaurus_, possess well-developed lateral-line canals (458). H. von Meyer (428) many years ago made out the course of the canals in _Archegosaurus_. The greater part of the following description is based on _Eryops megacephalus_ Cope from the Texas Permian. The entire surface of the cranial elements in _Eryops_, as in other of the Stegocephala (458), is covered with coarse pits. The fossæ are present even in the bottoms of the grooves which represent the lateral-line system, and are more marked in the members of the Temnospondylia than in the Stereospondylia.