ON A SPINAL COLUMN OP LOXOMMA ALLMANNI. 353 



their zygapophyses are less evident. No. 1 1 has a broad spinous 

 process; that of No. 12 shorter, and as if bent over. On all 

 these bodies there are costal articular facets. 



Beyond the neural spines of Nos. 10 and 11 there are imbed- 

 ded in the matrix, and belonging to the right side of the column, 

 three portions of ribs; one of •which is merely a small fragment; 

 another is very strong, and has its head lying under the flat 

 spinous process of No. 9 ; the third, about one inch and a half 

 long, shows the oval superficial articular cavity of its head. 



On the lower side of this part of the column are four frag- 

 ments of ribs, lying nearly in the same direction as the column, 

 and Varying in length from four to six inches ; their heads are 

 not perceptible. 



Nos. 13 and 14 have lost their spinous processes, and through 

 No. 13 runs a fissure. No. 15 is imperfect. 



Nos. 16, 17, 18, and 19 have their neural spines nearly entire, 

 and these are one inch and a half wide at their top. Their 

 bodies are stout, and their zygapophyses in normal juxtaposition; 

 and on them are facets for ribs, very like those on Nos. 10, 

 11, 12, and 13. Lying under Nos. 14 and 15 are fragments of 

 five ribs massed together, and all broken off at the edge of the 

 specimen, 



Nos. 20, 21, 22, 23, and 24 have lost all processes; but each 

 has a well-marked facet for a rib. Below Nos. 21 and 22 are 

 lying four fragments of ribs, more slender than those above 

 mentioned. Under No. 24 is a small fragment of rib pointing 

 backwards, 



Nos. 25, 26, 27, 28, 29, and 30 are of diminished size. Below 

 No. 25 is a flat piece of bone, in width about one inch and a half, 

 not understood, but suspected of some relationship with a possible 

 pelvic girdle, and on this piece lies the head of the first of the 

 following series of costal bdnes, deserving of special notice. 

 They belong to the right side of the spine, and are seven in 

 number, with an indication of an eighth. 



Each of these peculiar ribs appears double, as if formed of 

 two ribs, united by a smooth, rather concave plate, each having 

 a small articular surface for articulation; the outer-lying one 



