i6o 



PATAGONIAN EXPEDITIONS: PALAEONTOLOGY. 



succeeds the atlas is made up of the axis fused with the third and fourth 

 cervicals, thus consisting of three vertebrae, instead of four as in Propal- 

 (Bohoplophorus. As the individual is fully adult, this difference cannot be 

 attributed to age and is not without importance. 



MEASUREMENTS. 



Upper dentition, length 093 



" " i to -6- inclusive., .050 

 1, length (i. e., antero-posterior diame- 

 ter) 004 



length 006 



" on 



width (i. e., transverse diameter) 004 



length 0125 



" width 006 



i, length 0115 



" width 007 



, length 01 2 



" width 007 



Skull, extreme length ? .140 



Cranium, length to rim of orbit 106 



" width at postorbital constric- 

 tion 036 



" over zygomatic arches. .097 

 " postorbital pro- 

 cesses 05 2 



Occiput, height 041 



" breadth 053 



distance between condyles 027 



Basioccipital, posterior width 027 



Basioccipital, anterior width 



Zygoma, length 



" dorso-ventral width 



" length suborbital process .... 

 "J width over suborbital pro- 

 cesses 



of suborbital process at 



distal end 



Face, length ? 



Rostrum, length ? 



width at base 



Palate, width at 1 



ft u n 8 



Atlas, length 



" width over anterior cotyles 



" of neural arch 



" " " inferior arch 



Axis, length of centrum 



" width of anterior face 



Third cervical, length 



Fourth " " 



" " width of posterior face . . 

 Compound cervical, length 



.012 

 .069 

 .022 

 .048 



.090 



.010 

 .040 

 .027 

 .045 

 .015 

 .023 

 ,017 

 .045 

 ,012 

 .008 

 .Oil 

 .042 

 .006 

 .010 



035 



027 



As a more convenient method of comparing the skull of this species 

 with that of Propalceohophphorus australis and clearly displaying their 

 differences of proportions, the following table of relative measurements 

 has been prepared. The distance from the anterior border of the occipital 

 condyle to that of the first upper tooth is taken as 100 and the other 

 measurements are calculated in percentages of that distance ; the calcula- 

 tion is not carried beyond the first decimal place. 



P. australis. M. anceps. 



Distance anterior border of occipital condyle to -1- 100 100 



Cranium, length to anterior rim of orbit 77.5 83.4 



" width at postorbital constriction 27.5 25.3 



