16 ARKIV FÖR ZOOLOGI. BAND 3. N:0 3. 



real foramen vertebrale, bnt an inward directed processus fi 

 the lower side of the diapophysis forms a kind of substit 

 to such a one. The neural spines are strong, almost ereci 

 the 3d to 6th vertebrse, still higher but directed obliqu 

 backwards (as in the thoracal region) in the 7th. 



The thoracal region embraces 14 vertebrae as there 

 14 pairs of ribs — against only 13 in O. afer^. In th 

 foremost thoracal vertebrse the met- and anapop hyses 

 small, but quite distinct from each other. Especially are 

 anapophyses easily seen. On the fourth thoracal verte 

 the metapophysis begins to project more, but both sit 

 the end of the diapophysis. From the 9th thoracal verte 

 and backward they begin to increase more rapidly in i 

 and the metapophyses move inward so that already on 

 llth it sits on the outer side of the praezygapophysis anc 

 directed obliquely forward upward. On the 3 last thora 

 vertebrae it becomes more erect and also turned somew 

 outward. The anapoph3^ses keep their place on the end 

 the diapophyses and are directed backward, posteriorly a 

 a little more outAvard and upward. They do not incre 

 so much in size posteriorly as the metapophyses do. Th 

 processes look quite different in O. afer where they are sm{ 

 er and on the 7 anterior thoracal vertebrae are very lii 

 or not at all differentiated from each other. 



On the lower side of the last cervical and three antei 

 thoracal vertebrae there are a pair of knobs representing ri; 

 mentary hypapophyses. I ha ve not seen any such in O. a 

 The neural spines are long, third and fourth largest, m 

 suring 63 mm. From these the actual length is somewl 

 diminished to the tenth which is only two thirds as hi 

 but, as the posterior ones are more erect, all neural spii 

 form together a subequal crest. The llth is vertical anc 

 little broader. The 12th to 14th are also vertical and v( 

 broad (16-18 mm.) having the same shape as that of 1 

 anterior lumbar vertebrae. 



In correspondence with the increase in number of 1 

 thoracal vertebrae there are only 7 lumbar vertebrae. Th 

 neural spines increase in height to the 4th (57 mm.) I 



* 13 pair of ribs are stated by all autliorities from Cuviek, OwE^ 

 the most recent authors upoii the subject. The same number is seen 

 the specimens I have had for comparison. 



