36 REVISION OF THE PELYCOSAURIA. 



Theriodontia. In the translation of Zittel's Grundzuge it was referred to 

 the family Clcpsydropidcp in the Pelycosanria; it is now evident that it must 

 be transferred to the family Poliosatiridcc of the Pclycosatiria. 



The spines are short, there are abdominal ossicles, and the limb bones 

 have well-developed articular surfaces. From the size and appearance of 

 such bones as are preserved it is apparent that it belongs close to the genus 

 Theroplc2ira. 



Family CLEPSYDROPIDAE Cope. 



Proc. Am. Phil. Soc, vol. xvin, 1878, p. 529. Also Pal. Bull. 29. 



Original description: "The division Pelycosanria is established primarily on the 

 genera Clcpsydrops and Dinietrodon, but their cranial structure renders it highly 

 probable that Ectocynodon, Pariotichus, and Bolosaurtis belong to it. It is also prob- 

 able that the genera Empedocles, Emholopliorns, and others determined from vertebrte 

 belong to it, as the latter are frequently accompanied by pelvic bones of the type of 

 that of Dimetrodon. All the genera known from teeth and crania are of carnivorous 

 habit, excepting Bolosanrns and Diadedes ; they may be referred to a single family 

 on this account, which I call the Clepsydropidcc. Bolosanrns will form the type of 

 another famih- characterized by the transverse position of the crowns of the teeth, 

 under the name of the Bolosanridcc.'''' 



It is seen from this that the family was founded simply on the carniv- 

 orous character, but as it comprised forms now known to belong to other 

 families and orders, and as the carnivorous character is ordinal in value, it 

 becomes necessary to define the order from entirely different characters. 



Redescription of family : 



(i) Skiill laterally compressed and facial region elevated. 



(2) Tooth line of skull convex. 



(3) Neural spines very high. 



(4) Sacnam with three vertebrse. 



In 1882 (54), p. 450, the genus Edaphosanrus was described and placed 

 in a distinct family, EdapJiosauridcF, "distinguished from the Clcpsydrofidce 

 by the presence of more than one series of teeth on parts of the jaws." The 

 family included Panlyhis, EdaphosaJirus, and perhaps Helodedes. 



In 1883 (56), p. 631, Pariotichus, Pantyhis, and probably Ectocynodon 

 are referred to a new family, Parioticliidcp, "which has the teeth like the 

 Edaphosaiiridce, but differs from it in the entire over-roofing of the temporal 



fossse." 



In 1888 (70) the family EdaphosatiridcB was dropped and the genus 

 Edaphosaunis was included in the Clepsydropidcr. This was the last change 

 made in the composition of the family which was considered to hold the 

 genera fLysorophns, Archcobolus, Clcpsydrops, Dimetrodon, Naosaurus, 

 Theropleura, Embolophortis, and Edaphosanrus. 



