HELIX-PLECTOTROPIS. 193 



Martens adopts the sectional name Philidora for this and H. 

 gabata Gld. 



H. MACKENSII Adams and Reeve. PI. 52, fig. 53. 



One of the original figures is here reproduced, for comparison 

 with the following forms. The figure given in Vol. IV, pi. 11, fig. 

 34, is a copy of the original figure of the face of the shell. 



Var. MYSTAGOGA Mabille. PI. 52, figs. 54, 55. 



This is a smaller form than the typical mackensii. My figures 

 are drawn from the type in collection 1'Abbe A. Vathelet. 



China. 



Helix mystagoga J. MABILLE, Bull. Soc. Philomath, de Paris, 

 1887-1888, p. 73. 



Var. VULGIVAGA Schm. and Bttg. PI. 52, figs. 56-60. 



Differs from typical mackensii in the greater width of the umbili- 

 cus, five-sixteenths the diameter of shell ; the smaller more solid, 

 shell always corneous-yellowish, the spire always higher, more or 

 less elevated ; last whorl distinctly deflexed in front ; aperture gen- 

 erally less angulated above. 



Alt. 12-13, greater diam. 24-25 J mill. ; alt. of aperture 9, width 

 8f mill. (S. tt- .) 



Kobe, Niphon, Japan. 



H. (Plectotropis) mackenzii v. vulgivaga S. & B., Nachr.-bl. d. d. 

 Mai. Ges. 1890, p. 136. H. mackensii KOBELT, Faun. Jap., p. 19, 

 t. 2, f. 1-2. 



H. SHERMANI Pfr. var. LAUTSI Schmacker & Boettger. PI. 53. 

 figs. 63, 64, 65. 



Shell moderately umbilicated, (umbilicus about one-sixth the 

 diameter of shell) conic-depressed, acutely carinated ; horny-yellow- 

 ish, thin. Spire little elevated, slightly convex conic ; apex 

 slightly obtuse. Whorls 6J-7, nearly flat, separated by an 

 impressed, delicately white hair-lined suture ; lightly striatulate 

 and very densely spirally lineolate ; the last whorl having a sub- 

 compressed whitish carina, somewhat flattened below, spirally 

 impressed at the carina, rather sloping at the umbilicus, very little 

 deflexed in front. Aperture very oblique, rounded rhombic, the 

 right margin angled, terminations of lip very widely separated, the 



upper slightly reflexed, little arcuate, the lower curved, reflexed, 

 13 



