PLECTOPTLI8. 127 



Parietal wall with two transverse oblique laminae converging 

 upwards, the posterior one rather thin, slightly sinuous, and 

 having a short ridge posteriorly at the upper and lower extremities, 

 the anterior one shorter, but much stronger and stouter, having 

 an ascending ridge posteriorly above and a short stout support 

 posteriorly below; on the anterior side are found two strong 

 horizontal folds, the lower stout and short and becoming suddenly 

 attenuated ; the upper fold long, rather thinner, following the 

 deflection of the last whorl and terminating close to the ridge at 

 the aperture, but not being united to it ; a very thin horizontal 

 fold rises below the transverse laminae close to the lower suture, 

 runs parallel with it, and terminates at the ridge at the aperture. 

 Palatal folds, 5 : the first near the suture, straight and nearly 

 horizontal ; the second a little more oblique and deflected poste- 

 riorly ; the third nearly horizontal, but more deflected posteriorly; 

 all three have a slight indentation near the posterior extremity 

 forming a bead-like termination ; the fourth is vertical, deflected 

 a little anteriorly above and posteriorly below, having posteriorly 



Fig. 62. Plectopylis leucockila. 



a small denticle near the lower extremity and another about the 

 middle ; the fifth is near the lower suture, horizontal and deflected 

 at both extremities." (Gude.) 



Major diam. 15-17, minor 12-14 mm. ; alt. 6-7 mm. 



Hob. Burma. 



Five specimens received from Mr. Fulton as P. leiopJiis proved 

 upon examination to be distinct, and to belong, in fact, to a 

 different section of the genus. 



Plectopylis leucochila is allied to P. ponsonbyi, but differs from 

 it in the more raised spire and in having a deeper and more 

 perspective umbilicus. In the armature it differs from the other 

 members of the group of P. ponsonbyi in having the upper parietal 

 fold uninterrupted. Figs. 62 a-c show the shell in three different 

 aspects, natural size, while figs. 62 d and e are enlarged ; the 

 former shows the parietal wall with its laminae and folds, and the 

 latter the inside of the outer wall with the folds and denticles. 



A specimen in the Blanford collection, labelled " H. F. Blan- 

 ford," I refer to this species. 



