PLECTOPYLIS. 



129 



shorter horizoutal lamella from the bottom ; the hinder with small 

 re-entering supports above and below. Beneath both is a narrow 

 free thread-like horizontal lamella. Palatal teeth 5 : 1st, 2nd, 

 3rd, and 5th horizontal, 4th vertical and stouter than the others ; 

 1st and 2nd longer than the remainder," {Blanfonl.) 



Major diam. 16, minor 13 mm. ; alt. 4:5 mm. 



Hah. Burma : Prome (Fedden, Blanford, JTungerford, Fea) ; 

 Thjet-Myo (Blanford). 



Ill, Plectopylis cairusi, Gude. 



Fkctopylis cavtisi, Gude, Science Gossip, n. s. v, ]898, p. 17], 



fig. 90 (shell and armature). 

 Plectopylis (s. s.) cairnsi, Gude, op. cit, vi, 1899, p. 148. 



Orifjinal description : — " Shell sinistrorse, discoid, solid, widely 

 umbilicated, yellowish corneous, finely and regularly ribbed, and 

 decussated with microscopic spiral lines. Spire depressed, apex 

 scarcely prominent, suture distinctly impressed ; whorls 54, 

 tumid above, rounded below, increasing slowly and regularly, the 



[^E^ 



e f g 



Fig. 64. — Plectopylis cairim. 



last descending moderately in front ; aperture oblique, cordate, 

 a little inflexed at the upper outer margin. Peristome wliite, 

 strongly thickened and reflexed ; the margins united by a strong 

 raised tiexuous ridge on the parietal callus, notched at the 

 junctions above and below. Parietal wall with a strong median 

 fold given off from the apertural ridge, revolving round about 

 a quarter of the last whorl, but interrupted at the middle ; near 

 its posterior extremity occurs a branched fold in the form of the 

 Gi'eek letter X, i. e. an obliquely ascending fold, haying anteriorly 



