114 



GUDE : NEW AND UNFIGURED SPECIES OF PLECTOPVLIS. 



a little thickened and shortly reflected, margins approaching, united 

 by a thin raised flexuous ridge on the parietal callus, which gives off a 

 thin, short, slightly ascending fold. Parietal armature composed of 

 two transverse plates, the posterior crescent-sha]:)ed, deflected posteriorly 

 below, thinner and slighter than the anterior one, \\hich is vertical and 

 gives off at the upper extremity a strong support anteriorly and a 

 slight ridge posteriorly ; at the lower extremity occurs a short support 

 anteriorly, and a long fold posteriorly reaching to the lower extremity 

 of the posterior plate. Palatal armature composed of six folds : 

 the first slight, thin, horizontal ; the second oblique, its anterior 

 extremity attenuated, its posterior extremity clavate, a little reflected 

 upwards: the third and fourth subvertical, their posterior extremities 

 attenuated and obliquely deflected ; the fifth also subvertical, the 



d. f. 



Figs. 3r. — 3f". — Pkclvpylis [Endoplon) 2'hhjarla , Mab. 



posterior extremity obliquely deflected, bifurcate : the sixth obli{iue, 

 sinuous, thin and shorter than the preceding four. 



Major diam. 15, minor 13; alt. 6"5 millim. 



//a?^.— Than-Moi. 



A long lost shell, apparently not found since it was described by 

 Mr. Mabille. It was not amongst the shells collected by Col. Messager. 

 The armature was not hitherto known and I am pleased to have this 

 opportunity of examining and figuring these important structures. 



Among the specimens with which Mr. Fruhstorfer has flavoured 

 me are a number of immature shells. One of these has only 3^- 

 whorls completed, but both armatures are already ibrmed : the anterior 

 parietal plate is distinctly notched at the upper and lower extremity, 

 at the junctions with the horiiiontal folds ; the palatal folds are very 



