356 GEOLOGICAL SURVEY OF TEXAS. 



The ventral lobe is divided by a large bottle-shaped siphonal saddle divided 

 by a siphonal lobe at the extremity; the lateral branches of the ventral lobes 

 are very long and acutely pointed, as are also the first lateral lobes which 

 are of the same length as these branches of the ventral. The first lateral 

 saddles are hastate and acutely pointed and second lateral saddles are. as is 

 usual in this genus, sub-hastate. The inner outlines of these last are con- 

 cave near the points, then suddenly convex internally where the lobe of the 

 umbilical shoulder begins. These last mentioned lobes are also acutely 

 pointed but much more abbreviated than the other two pairs. The shell is 

 strongly striated, but it is not pilated or otherwise marked, except when con- 

 strictions occur. 



