1 66 University of Texas Bulletin 



Perrinites compressus nov. sp. 

 PI. X, Fig. 22-27 



Shell discoidal, involute, with compressed and flattened flanks, 

 rounded venter, greatest width near the umbilical shoulder. Whorls 

 deeply embracing, the involution being somewhat more than one-half 

 of the height of the whorl; the cross-section is parabolical, as the 

 height of the whorl is less than the width. No constrictions have been 

 observed on the type specimens, but this may be due to the state of 

 preservation. Both specimens are casts and no kind of ornamenta- 

 tion is visible on them. The umbilicus is narrow and deep, the umbili- 

 cal shoulder is rounded, the umbilical wall is steep. The body chamber 

 is unknown. 



The septa are very near together and in places nearly touch each 

 other. The suture (pi. X, fig. 25, 26) follows a straight line between 

 the sipho and the umbilicus. The siphonal lobe is divided in two 

 branches by a high median saddle ; each of the branches ends in a long 

 and sharp point. It tapers from the upper part toward the bottom. 

 The first lateral lobe is very little deeper than the branches of the 

 siphonal lobe, but broader, more symmetrical and more scalloped. 

 The second lateral lobe is similar to the first one in every detail. but 

 less deep and wide. The same may be said of the first, second and 

 third auxiliary lobes, although the last two are not very well preserved. 

 All the lobes decrease gradually in depth and width from the first 

 lateral to the umbilicus. The third auxiliary lobe lies on the umbilical 

 wall. 



The median saddle of the siphonal lobe is unusually high, broader 

 at the base than at the top, where it is notched by an indentation. It 

 has three secondary lobes on each side. The external saddle is very 

 high, broad at the base and narrow above; leaving out of considera- 

 tion the secondary lobes, the whole saddle has a triangular outline. 

 It is scalloped on each side by about three to four secondary lobes 

 which cause the existence of slender secondary saddles; all those on 

 the upper portion of the saddle end in phylloid points, one of them form- 

 ing the highest part of the saddle, while two more branch ofif, not quite 

 at the same height, somewhat below the upper end of the saddle, giv- 

 ing it a tripartite aspect. The secondary lobes become shorter grad- 

 ually nearer to the base of the saddle, where they form only small in- 



