412 PJROF. H. G. SEELET ON PSEPHOPHOETJS P0LYG0NT7S. 



It would appear that the absence of transverse processes in the 

 Chelonian, while so characteristic of the crocodile in the dorsal 

 region, may have come to be correlated with the mode of develop- 

 ment of the carapace, and the consequent way in which muscular ten- 

 sion on the bones was changed ; but when the carapace is free from 

 the ribs, the condition of the dermal skeleton is not very diiferent, as 

 regards its position and relation to the endoskeleton, from what obtains 

 among the Crocodilia ; and although Sphargis does not develop trans- 

 verse processes for the attachment of the ribs, it must be remembered 

 that SpJiargis is the only member known of a great division of the 

 Chelonia which must have included many types of organization, and 

 is probably as important morphologically as all the other Chelonia put 

 together. 



The anterior position, however, of the transverse process in one 

 vertebra, just behind the anterior articulation, is altogether in har- 

 mony with the Chelonian plan. There is no indication that the ribs 

 were attached by a double articulation to the transverse processes, 

 as among Crocodiles ; but then it may be remembered that this cha- 

 racter is only found in the first six or seven dorsal vertebrae of the 

 crocodilian skeleton ; so that I am led to believe that the many points 

 in common, both in soft and hard structures, which the Chelonian 

 and Crocodilian orders possess, lead us here to look for a group which 

 may have more nearly connected them than any form previously 

 known. In the characters which can be compared, PsepTiojpliorus 

 seems to me to differ more from existing Chelonians than they differ 

 among themselves ; and hence I believe it will prove to be the type 

 of a new subordinal division, which, however, it is impossible at 

 present to fully define in the absence of the more important osteo- 

 logical characters. The following classification gives in a condensed 

 form the results to which this study of PsepJiopJiorus has led up. 



The characters of the carapace indicate three primary divisions of 

 the Chelonian order : — First, the 



AspiDOCHELTiD^, Comprising Turtles, Emydians, and Tortoises, in 

 which the symmetrical bony carapace is covered with symmetrical 

 horny scutes ; secondly, the 



Peltochelyid^, including the Trionychidse, in which the symme- 

 trical bony carapace has a granular surface-structure, and is 

 covered by an undivided dermic substance without scutes ; and, 

 thirdly, the 



Deematochelyii)^, represented by the Sphargidae, in which the cara-i 

 pace is not developed, but is represented by a bony skeleton 

 within the skin, resembling a tessellated pavement. 



The remains are from Neudorfl, near the river March, which forms 

 the boundary between Austria and Hungary. Yon Hauer refers the 

 sandstone there to the second or upper Mediterranean series of the 

 Austrian Neogene. Eish-remains from this formation have been 

 described by Count Mtinster in his ' Beitrage zur Petrefactenkunde;' 

 and the deposit also yields Gasteropods, Bivalves, and Echini. 



I would express my grateful thanks to Professor Suess for direct- 



