220 University of Texas Bulletin 



and high. They become a little lower on the venter but cross it without 

 interruption; no longitudnal furrow exists on the venter. On the ventral 

 shoulders the ribs thicken a little, forming on each shoulder a row of ra- 

 dially elongated nodules ; these are not very strong and rather low. These 

 nodules make the ventral shoulders appear angular and the ventral zone 

 more flattened than concave. 



Figure 4. Sutures, Vascoceras mohovanense n. sp (above) and Mammites mohovan- 

 ensis n. sp. (below). 



The suture is very simple. The external lobe is quite wide and deep, 

 and bifid ; the external saddle is broad, low, or a rounded form and a little 

 ramified ; the first lateral lobe is wide, approximately as deep as the exter- 

 nal lobe but much wider, and it ends in two points ; the first lateral saddle 

 is very low, rounded and broad and lies in the umbilical nodule; the form 

 of the second lateral lobe, which lies mostly on the umbilical wall, can not 

 be well distinguished. 



Dimensions : 



Diameter 56 mm. (1) 



Height of the last whorl 21 mm. 0.38 



Width of the last whorl 45 mm. 0.80 (with the nodule) 



Diameter of the umbilicus 19 mm. 0.34 



Height of the last whorl on the same diameter but 



half a whorl backwards 16 mm. 0.29 



Width of the last whorl at the same point 34 mm. 0.61 



This very characteristic species certainly belongs to the group of Vasco- 

 ceras sub conciliation Choffat 1 , but it resembles Vascoceras polymorphum 



1 Choffat, Espfcces nouv. ou peu conn., p. 64, pi. 15, figs. 1-3; pi. 16, fig. 4; pi. 22, 

 figs. 28-31. 



