ART. 14. 



MARYLAND FOSSIL POEPOTSE — KELLOGG. 



Measurements of lumbar vertebrae {in millimeters). 



33 



Greatest depth (vertically) of vertebra (tip of neural 

 spine to inferior face of centrum) 



Height of anterior face of centrum 



Breadth of anterior face of centrum 



Height of posterior face of centrum 



Breadth of posterior face of centrum 



Greatest length of centrum 



Distance across vertebra between tips of the transverse 

 processes (as preserved) 



Distance between the tip of left post-zygapophysis and 

 tip of left pre-zygapophysis (as preserved) 



Minimum length of neurapophysis 



Antero-posterior breadth of neural spine in a horizontal 

 line immediately above the zygapophyses 



Antero-posterior diameter of left transverse process at ex- 

 tremity 



Vertical height of neural spine (distance between supe- 

 rior margin of spinal canal and tip of spine) 



196 



57 



X 



62 



X 



103 



277 



X 

 X 



76 



X 



211 

 61 



X 



X 

 X 



111 



55 

 80 



58 



108+1 119 



242.0 

 69.0 

 78.0 

 72.0 

 82.0 



123.5 



26L0 



144.0 

 63.0 



99.0 



90.0 



148.0 



CAUDAL VERTEBRAE. 



Onl}^ three caudal vertebrae have been preserved and they belong 

 near the distal end of the series. In form they somewhat resemble 

 the caudals of Inia geojfrensis though the vertebral canals are rela- 

 tively larger than in Inia. The largest of these caudals (pi. 18, fig. 

 5) is almost circular in outline, while the remaining two (pi. 18, 

 figs. 6-7) are smaller and somewhat flattened dorso-ventrally. The 

 "iides of both of the last-mentioned caudals are grooved. 



All of these caudals are pierced dorso-ventrally by two large ver- 

 tebral canals. On the ventral face of the largest caudal (pi. 17, 

 fig. 1) there are two openings for each vertebral canal of which the 

 external ones are nearly closed. The double keels on the ventral 

 face of the largest caudal are approximately parallel and inclose 

 a narrow concave area. The vertebral canals converge ventrally and 

 in the small terminal caudals (pi. 17, figs. 2-3) open only into the 

 longitudinal depressed area. The ventral openings of these canals 

 are partiallj' concealed by overhanging bony shelves. The dorsal 

 openings of the vertebral canals (pi. 17, figs. 4r-6) are large and 

 wide apart. 



The presence of a pair of neurapophyses on the largest caudal 

 shows that all of the caudal vertebrae with the exception of the ter- 

 minal ones possess a neural arch. The neurapophyses of the largest 

 caudal (pi. 17, fig. 4) converge mesally and partially close the neural 

 canal posteriorly. The anterior articulating surfaces of the caudals 

 (pi. 18, figs. 5-7) are concave, while the posterior are convex. 



