FAUNA OP THE G0SAT7 FOKMATION. 



691 



of the inferior margin of the cup of the centrum, which gives a slight 

 appearance of leaning forward to the bodies of the vertebras. The 

 twelfth centrum is 22 miilim. long, and has the cup 13 millim. wide 

 in front, showing an increase in the depression of the centrum simi- 

 lar to that which is observed in the later dorsal vertebras of existing 

 Crocodiles. 



Lumbar Vertebra. 



The lumbar vertebra (PI. XXX. figs. 10, 11) may not have been 

 the only one of its kind ; it certainly did not immediately succeed 

 the last dorsal, if it is supposed to have pertained to the same 

 animal ; for it has the centrum much more depressed, with the zyga- 

 pophysial facets perceptibly higher, but still retaining a much less 

 inclined position than is seen in the Alligator. The cup in front of 

 the centrum (fig. 10) is 1^ centim. wideband, as preserved, 1 centim.in 

 vertical diameter ; so that it has a transversely oval form, which gives 

 a broad aspect to the base of the centrum. The posterior ball has a 

 similar pterodactyle-like transverse extension, but, as in the earlier 

 vertebras of the series, is margined above by the characteristic groove. 

 The transverse process is only 7 millim. wide at the base, and was 

 therefore small, like the corresponding process in the Alligator. 

 In transverse section (fig. 11) it is somewhat T-shaped, owing to the 

 development of an inferior sharp vertical ridge which descends to 

 the base of the neural arch, widening as it comes downward. This 

 ridge curiously resembles that which is so characteristic in the neural 

 arch of a Dinosaur ; but it is clearly comparable to that which I have 

 referred to in the early dorsal vertebra, and constitutes one of the 

 distinctive characters of the species. The neural canal here enlarges 

 again as though in anticipation of the sacral expansion. The notch 

 between the posterior zygapophyses is wider in this vertebra than in 

 the dorsal series ; and the zygapophyses appear to be somewhat 

 stronger and broader. 



Saaral Vertebra. 



The first sacral vertebra is only a fragment, the greater part of the 

 neural arch being broken away, only a portion of it remaining at the 

 anterior end of the left side. The centrum is remarkably oblique ; it 

 is 2 centim. long, and flattened on the under side, with a small median 

 groove in the anterior part. The sides are rounded ; the anterior cup 

 is imperfectly preserved, but appears to have been more depressed 

 than in the lumbar vertebra. The posterior end of the centrum is 

 oblique, flattened, with a depression below the neural surface. It is 

 narrower than the anterior end, being about 11 millim. wide, as pre- 

 served, and semicircular in outline. The basal surface of the neural 

 canal is smooth, straight, and concave from side to side. The neural 

 arch enters into the anterior cup as in the Alligator, and gives off at 

 the anterior end of the side a massive transverse process, the frac- 

 tured base of which is 13 millim. deep and 1 centim. wide, and has 

 a somewhat reniform outline owing to the anterior concavity. Only 

 the base of the anterior zygapophysis is preserved. 



2z2 



