124 University of Texas Bulletin 



deep as the first one and much narrower. The third auxiUary lobe, 

 which lies on the umbilical shoulder, is small, funnel-shaped, and ends 

 in a point. Very similar to it is the fourth auxiliary lobe which Ues 

 on the umbilical wall. 



The median saddle of the siphonal lobe is short, relatively broad, 

 very slightly constricted near its middle, deeply notched at the top by 

 an indentation. The external and the first lateral saddles are of a very 

 similar shape. Like all the rest of the saddles they are entire and 

 rounded at the top; they are about of the same height, symmetrical, 

 slender, and nearly double as high as the median saddle of the siphonal 

 lobe; the first lateral saddle is much narrower than the external one. 

 The second lateral saddle is similar in shape to the first and the exter- 

 nal, but much lower. The first, second, and third auxiliary saddles 

 show practically no constriction and decrease gradually in height. They 

 are all lower than the second lateral. The third auxiliary saddle lies 

 on the umbilical wall. 



Dimensions : 



Diameter 13.3 mm (1) 



Width 10.5 0.79 



Height of last whorl 6.3 0.47 



Diameter of the umbilicus , 1.6 0.12 



G-eneric position: 



In its external shape our species is very similar to Agathiceras 

 Girtyi n. sp., although its ventral part is decidedly flattened, while that 

 of the latter species is rounded. Unfortunately, no trace of the orna- 

 mentation is preserved, but we know that the difference in ornamen- 

 tation between Agathiceras and Adrianites is not very great. In gen- 

 eral our species has the same type of lobes and saddles as Agathiceras, 

 but their number is much greater and the shape of the siphonal lobe and 

 its median saddle is certainly different. The median saddle is much 

 lower and relatively broader than that of any known species of Agathi- 

 ceras. In this latter genus the two branches of the siphonal lobe are 

 similar in shape and size to the first lateral lobe. This is not the case 

 in our species, those branches being very narrow and curved with the 

 convexity toward the outside. This is the form of the siphonal lobe of 

 every Adrianites described until now, not only the Sicilian ones, but 

 also the Russian. Different from it is only Adrianites sp. ind., de- 



