130 Kansas Academy of Science. 



tremity. The bone distally is curved strongly backward, so that 

 its articular surface looks backward at an angle of about twenty de- 

 grees. So far I have found no complete epipodial bone, though 

 doubtless a careful search of the Orlando material will reveal such. 

 The extremities of a number of epipodials are shown in the figures 

 (pi. 3). They are parts of the tibia and fibula. Associated with 

 No. H51 are four metapodials attached and lying parallel, or nearly 

 so, in the matrix. They are simple bones, as one would expect, 

 with the shaft moderately constricted, the extremities truncate. 

 It is very evident that the hind extremities were more slender 

 than the anterior ones, and probably longer, preserving more of 

 the terrestrial characters, and doubtless also of use upun land. 

 Nevertheless their size, in comparison with that of the vertebrae, 

 is small. 



In none of the Texas material at command is there any evidence 

 whatever of dermal ossifications, other than the clavicular gridle. 

 Nor do I find any certain evidence of such from the Orlando ma- 

 terial. Dermal plates are there in abundance in this material, but 

 none intimately associated with Diplocaulus bones; whereas speci- 

 mens of Cross'Aelos, another form which must for the present be 

 located with Diplacaulus among the Microsauria, though aberrant, 

 show abundant evidence of ventral ribs and probably also dermal 

 scutes. All of which goes to show that Diplocaulus was a bare- 

 skinned amphibian of predominantly aquatic habits, capable, how- 

 ever, of progression, doubtless with much labor, upon land. Its 

 position among the Amphibia is not assured In the complete 

 ossification of the vertebrae it has its nearest relationship among 

 the Microsauria, the Lepospondyli of Zittel, in which group it was 

 placed by Cope when he recognized the amphibian nature of the 

 genus, and to which it has also been assigned by Broili and Jaekel. 

 Furthermore, in the structure of the skull, notwithstanding its ex- 

 traordinary shape, it offers no important differences from that 

 group so far as is known; the epiotics are enormously developed, 

 it is true, but the epiotic notch is still preserved on the side. 



In the articulation of the ribs, however, there is a profound dif- 

 ference, one which seems to ally the type with the modern Urodeles, 

 as Cope intimated in his early descriptions. The true microsau- 

 rians have single-headed ribs attached intercentrally, or at least 

 the capitulum is always so attached — in Diplocaulus the elongated 

 diapophyses arising from the arch, and the equally elongated para- 

 pophyses from the centrum near the middle anteroposteriorly. 

 There is perhaps no more important ordinal character among the 



