474 



M. Talbot — Podokesaurus holyokenais. 



Fig 



the cavity of the centrum of 4"' m while the height of the cav- 

 ity is 5-5'"" 1 (fig. 4). 



The caudal vertebrae are only a little expanded at the ends and 

 are very slender throughout their length. A typical one is 17" im 

 long with a diameter of 4 mm at the ends. The neural spines, if 

 such they are (tig. 3, D.-G.), are of different shapes. These 

 caudal vertebra? are so nearly of a size, one with another, that 

 there is no apparent tapering of the series and 

 it is not clear which is the proximal end of 

 the tail nor is it possible, as yet, to estimate 

 its length. 



Ribs. — Quite a number of ribs (fig. 1, R.) 

 are visible, all very slender and hollow, but 

 the proximal end is not exposed save in one 

 instance where the bone is so broken that the 

 outline is not distinct. Near this proximal 

 end, however, the bone is somewhat concave 

 and expanded as if it might be bifurcate (tig. 

 1, R'). The largest rib'uncovered is 52 mm 

 long and 2 mm wide toward the proximal end, 

 while in no place does the thickness seem to 

 be more than l mm . The most anterior of the 

 cervical vertebras preserved have long ribs. 

 These are on another piece of the bowlder 

 and are not figured. 

 Just anterior to the distal end of the pubis there is a small 

 cluster of gently curved abdominal ribs (tig. 1, A. R.), exceed- 

 ingly slender and dove-tailed as- they lie in the rock, the 

 jDosition due, probably, to slipping. This mass of interlacing 

 ribs covers a space of 40 mm by 23 mm . There are at least eleven 

 of these ribs on each side of the median line, the largest of 

 which is 18 mm long and so small in diameter that the bone 

 looks like a mere thread in the rock. Slender as are these ribs, 

 they seem to be hollow. 



Sternal element ('{). — In the center of this mass of abdominal 

 ribs is a small body that responds to dilute hydrochloric acid, 

 as do' all of the bones. The part exposed measures 5 mm by 

 3 mm . This may be one of the sternal elements displaced. 



Gastrolith. — -Lying 10 mm away, and still among these ribs, is 

 a small piece of quartz, a flat, well-rounded pebble, l m,n thick 

 and 10 mm long. The width exposed is 4 mm , but more of the 

 pebble is embedded in the rock. There are no other pieces of 

 cpiartz larger than a grain of sand visible in the bowlder, and 

 considering this fact, considering, also, its smooth, polished 

 surface* and its position, the writer concludes that this must 



*Dinosaurian Gastroliths, G. R. Wieland, Science N. S., xxiii, pp. 819- 

 821. 



Fig. 4. Cross 

 section of cervical 

 vertebra showing 

 hollow construc- 

 tion, x 2. 



C. Cavity of cen- 

 trum. N. Neural 

 canal. 



