8o REVISION OF THE PELYCOSAURIA. 



slender and thin and are not elevated; on the side of the neural spines of the mid- 

 dorsals are paired rugose tuberosities, " knotchenartige Anschwellungen," which 

 Dr. Broili in correspondence likens to the process on the spines of Naosaitrits. The 

 diapophyses occur on all vertebrae ; the outer end is about level with the upper end of 

 the intercentra. Intercentra occur between all vertebrse posterior to the axis ; they 

 are very strong and the lower surface is broad and smooth, presenting a marked con- 

 trast to the keels of the adjacent centra. 



The sacral vertebrae resemble the nearest presacrals; the diapophyses are united 

 to the sacral ribs without suture. 



The caiidals bear chevron bones, but none are preserved in sufficient perfection 

 to warrant description, though it seems probable that they lie with their anterior bor- 

 der on the lateral and lower edges of the posterior border of the preceding vertebrse 

 rather than to originate from intercentra. 



^\).& presacral ribs were originally described as single-headed, but in response to 

 a request Dr. Broili has most kindly reexamined his specimen of / 'araiiosanriis and 

 writes as follows : " Unter der Praezygapophyse entspringt eiiie ungemein kraftige — 

 dornahnliche — Diapophyse, welche (bei besonders guter Erhaltung) nach initeii in 

 eine schmale, schwache Lamelle auslanft. 



" Der Rippenkopf, der nur in einem einzigen Stiicke gut zu erkennen ist, ist 

 demgemass ziemlich langsgestreckt. (Vergleisch S. 74 u. 75. [No. 14 in bibliog- 

 raphy.]) 



" Da, wie Sie sageu, die Ihnen bekanten Pelycosaurier, alle zweikopfige Rippen 

 besitzen, so eiitspricht vieUicht die Leiste unter Diapophyse von I 'aranosaiinis einem 

 nun mehr rudivietitdren Capiiitliim der Rippe. 



"Diese Leiste sowie auch die Rippe sind nur in einem Falle erhalten. (Fiir die 

 Rippen bitte ich Tafel X, Fig. 2, hinter dem Biichstaben J. zu vergleichen.) 



" Est diirfte daher die stellung von Varanosaurus unter den Pelycosaurier kin- 

 swegs deshalb eine so isolierte sein." 



This seems to show that the capitulum, though small, is present and the ribs are 

 truly double-headed. The anterior of the two sacral ribs has a broad, shovel-like dis- 

 tal end, the second is inclined forward with its distal end underlying the first. 

 The shoulder girdle is too poorly preserved to show characters of value. 

 The pelvic girdle: The bones of the pelvis are closely united, the sutures are 

 closed. The shape of the pelvis is surprisingly like that of Dimetrodon. 



The humerus is broken so that the two ends can not be placed together, but the 

 form was evidently close to that of Labidosaurus. The proximal half is proportion- 

 ately small, but the articular face is broad. There is a prominent deltoid crest. The 

 lower end shows a well-developed entepicondyle (die innere (Partie) sehr fliich in 

 einem lappenformigen Fortsatz auslanft). 



Th^/eviur is represented by the distal and proximal ends, but the middle por- 

 tion is wanting, so that the true length can not be given. The proximal end has no 

 true head, but has a rough articular area which gradually contracts toward the other 

 side. The anterior face of the proximal end is deeply concave and there is a promi- 

 nent trochanter. The distal end is divided by a deep cleft into two parts, both bear 

 articular faces. The inner part is directed forwards and down for the tibia, the outer 

 part has two faces, one directed forwards and downwards for the fibula and the back- 

 wards and upwards for the tibia. The tibia and Jib/da are slender and elongate. 



The calcaneus is flat, five-sided, and unites with the fibula and astragalus. The 

 astragalus is more irregular in form than the calcaneus, but stronger and larger. The 



