70 THE EXTINCT BATRACHIA, EEPTILIA 



r n. 



Lin. 



1 



5. 





6.5 





C.5 



1 



7. 





6.25 



1 



7.5 





10.5 



surements. 



Third cervical, total length, 



Crest of shoulder to outer angle parapophysis, 



Last point to plane of cup rim, 



From middle hall to apex neural spine, 



Least width of base of centrum, 



Sixth cervical (larger individual), length, 



Vertical diameter between rims of cup, 



The expanded bases of the neurapophyses leave only the cariniform epapophysis between them. 



Dorsal vertebral. — The first, third and fourth with the parapophysis on the centrum have lost only their neural 

 arches. The parapophyses have convex articular surfaces, which have a very posterior direction and are followed by 

 a deep depression in the side of the centrum ; in the first they are a little behind the middle of the side of the body. 

 The hypapophyses of all are distinguished by their lack of compression and their obtuseness. They are directed 

 vertically downwards, the anterior face posteriorly. That of the first is bifid as broad as long, the others simple, 

 longer than broad on the third. They are preceded by a depression behind the rim of the cup, and succeeded by 

 a second, simple, small hypapophysis near the shoulder, which is finely many-grooved ; it exists as a trace on the 

 third, which of all the dorsals, may alone be said to present a very obtuse carina below. The surface in the first 

 three is striate next the rim of the cup ; on the shoulder on the first two. The sixth dorsal is more compressed and 

 smoother : its cup is more produced upwards and outwards, while that of the first is more nearly round, and the 

 others are intermediate. 



The articular cups of dorsals near the seventh and eighth are nearly round, slightly deeper than broad. The. 

 horizontal width of the diapophyses is considerable, and the transverse extent of the articular (inferior) surface of 

 the posterior zygapophysis is equal one-half the length of the centrum between shoulder and cup. 



The seventh dorsal of the adult is perhaps twice as large as the above, without being half as large as the same 

 in the H. obscurus. Though the centrum is as much compressed as that of the sixth, the cup is still broader than 

 deep vertically. The centrum has a lateral longitudinal obtuse ridge. The hypapophysis is remarkably large for the 

 position in the vertebral column. It is trigonal in profile with truncate planes before and behind, the anterior 

 concave. The costal articular face is half way to the extremity of the diapophysis on its anterior margin. It is 

 transverse, not vertical as in the sixth in II. tenebrosus. 



Sacral. — The first exhibits a longitudinal concavity on the posterior half of the centrum below. 



Caudals. — The body of an anterior caudal is not compressed, those of three others, but slightly so ; the 

 cup of the first is round ; those of the others deeper than broad. Three have stout diapophyses ; of these the two 

 posterior have a concave inferior face separated by a strong angle from the sides, while there is an additional lateral 

 angulation on the anterior part of the side of the more anterior. In the two anterior, the neural spine is twice 

 constricted from base probably to near apex, leaving an anterior laminiform portion, and a median much stouter. In 

 the caudals the suture of the neural arch is much obliterated. 



Measurements of Vertebra). 

 Of Adult. 

 Seventh dorsal ; total length, 



depth articular cup, 

 width, 



longitudinal width neural arch (greatest), 

 " " diapophysis, 



Of Young. 

 Sixth dorsal ; total length, 



length to shoulder, 



depth neural canal to eud . hypapophysis, 



" articular cup, 

 width " " 



In. 



Lin. 



1 



8. 





10.5 





12. 



1 



8. 





11. 



In. 



Lin. 



1 



5. 



1 



1.5 



1 



1.5 





9.35 





11. 



