PLATE XXXI. 



Teipleuroceras Robsoni (page 281). 



Outline of the exposed] portion of an imperfect cast of the interior of 

 ■the shell of a specimen of this species, from Stonewall, presented by Mr. 

 Donald Gunn. This cast has fifteen septal chambers and a considerable 

 portion of the body chamber preserved, and shows the curved sutural 

 lines on the^flattened~and presumably abdominal side. The figure is 

 very slightly reduced in size, biit not more so than by about one-eighth 

 of an inch. 



