94 University of Texas Bulletin 



even a little broader, the greatest width being at the umbilical shoulder. 

 The involution is one-third of the height of the whorl. The umbilicus 

 is moderately narrow, and deep; the umbilical shoulder is somewhat 

 rounded but fairly distinct; the umbilical wall is broad and perpendi- 

 cular. No constrictions are visible on the mould. In none of the speci- 

 mens could any trace of the ornamentation be observed. The body 

 chamber is unknown. 



The septa are very near together but do not touch each other. The 

 suture (pi. Ill, fig. 12, 1 6) follow a straight line between the sipho 

 and the umbilicus. The siphonal lobe is divided into two branches by 

 a high median saddle. Each of the branches is broad and long, asym- 

 metrical on account of the umbilical side being sinuous, while the si- 

 phonal side is only slightly curved; the branch ends in a sharp point. 

 The first lateral lobe is symmetrical, tongue-shaped, pointed, wider 

 at the top than in the nTiddle, much shorter than the branches of 

 the siphonal lobe. The second lateral lobe is broader than the first one 

 but less deep; it is also tongue-shaped and pointed. A small tongue- 

 shaped, or perhaps rather funnel-shaped, pointed auxiliary lobe exists 

 near the umbilical shoulder. 



The median saddle of the siphonal lobe is extremely high and very 

 slender, it is broader at the base than at the top, where it is deeply 

 notched by an indentation; the sides are slightly concave, but do not 

 show a constriction. The saddles are all spatulate, rounded above 

 and not constricted. The external saddle is high and narrow, a little 

 higher than the median saddle of the siphonal lobe. The first lateral 

 saddle is comparatively stouter than the external one and about as high 

 as the median saddle of the siphonal lobe. The second lateral saddle 

 is still a little stouter than the first one and also somewhat lower. A 

 small rounded and simple auxiliary saddle lies on the umbilical border, 

 part of its umbilical flank remaining on the umbilical wall. It was 

 impossible to uncover the suture on the umbilical wall and on the 

 dorsal part of the shell. 



Dimensions : 



Diameter 79.9 (1) 



Width 38.0 0.48 



Height of last whorl 40.8 0.51 



Involution 13.7 0.17 



Diameter of umbilicns 14.8 0.19 



