WILLISTON AND MOODIE : OGMODIRUS MARTINII. 63 



faithful and intelligent work in iibe Ci-fetaceous deposits of Kansas 



for the University of Kansas. 



The genus Ogmodirus {^y.'j "'drawn out in a straight line and 



'^^:/'^ neck) has been defined as follows:^ 



Cervical vertebrae short, almost as wide as long, gradually increasing in 

 size. The length and breadth are proportionate, as is indicated in the fol- 

 lowing table of measurements: 



Length. Width. 



Cervical vertebra 1 0.020 m. 0.030 m. 



Cervical vertebra 6 0.023 m. 0.032 m. 



Cervical vertebra 12 0.030 m. 0.038 m. 



Cervical vertebra 20 0.034 m. 0.044 m. 



Cervical vertebra 30 0.041 m. 0.052 m. 



Cervical vertebra 40 0.045 m. 0.067 m. 



Cervical vertebra 45 0.045 m. 0.067 m. 



Cervical vertebra 51 0.046 m. 0.072 m. 



Since there is nothing present of either the atlas or axis, the 

 first cervical vertebra preserved must be at least the third of the 

 series, possibly a later one. At any rate it is the first of the series 

 presented. No cervical ribs are preserved complete, though there 

 are fragments of them. The rib facettes are present throughout 

 the cervical series. (Fig. 1, text.) For a member of the Elasmo- 

 sauridse the neck is not extraordinarily long, containing probably 

 about sixty vertebras, and measuring about 2 meters. The pad- 

 dles are not expansive, but short and thick, with the metacarpals 

 and phalanges short and heav>^ 



The fore limb (plate II) has a complete length of 0.600 m., of 

 which 0.152 m. belongs to the propodium, 0.050 m. to the meso- 

 podium, 0.070 m. to the metapodium, and about 0.300 m. to the 

 digital portion. This is making no allowance for the cartilage, 

 ligaments and integument, which doubtless adds several milli- 

 meters to the length as given. 



Cervical vertehrse. These centra are, as usual, nearly amphi- 

 platyan. On the visceral surface they are, throughout the series, 

 perforated by a pair of vascular foramina (plate IV, fig. 5), which 

 have a diameter of 2 mm. On the fifteenth vertebra preserved 

 this opening measures 6 mm. There are two articular surfaces 

 for the articulation of the ribs (plate I). These articular surfaces 

 gradually increase in size toward the dorsal region. On the third 

 cervical they possess a length of 11 mm. and a breadth of 8 mm.; 

 on the fifteenth a length of 18 mm. and a breadth of 14 mm. 

 Superficially there appears over all the cervical centra many 



3. Williston, S. W., and Moodie, Roy L. 1913. A New Plesiosaurian Genus from the Cre- 

 taceous of Kansas. Bull. Geol. Soc. Amer., vol. 24, No. 1, pp. 120, 121. March. 



