ACMOPUPA. 101 



lessly broken that it is quite impossible even to determine to 

 what group of the genus it belonged. The original descrip- 

 tions and figures of these minute forms are hardly in them- 

 selves sufficient, and the Pretoria District, whence they were 

 recorded, has since been often carefully searched, and yielded 

 only the species mentioned [above]. It is probable that, if 

 ever the missing type of ha-ploa or cotypes of psichion turn 

 up, they will prove to be identical with some forms already 

 named; meanwhile no useful purpose can be served by re- 

 taining them in the list of collectible varieties." 



Genus ACMOPUPA Boettger. 



Acmopitpa BTTG., Jahrb. Nassau. Ver. Nat., xlii, 1889, p. 

 271. Monotype: Bulimus subtiUssimus Al. Braun. 



The shell is minute, perforate-rimate, elongately fusiform, 

 thin, glossy, nearly smooth ; apex rather obtuse. Whorls 4 to 

 5, a little convex, slowly increasing, the penult more flattened, 

 the last whorl forming one-third the total length. Aperture 

 oval, toothless, the margins converging, a little reflected, colu- 

 mellar margin somewhat concave (Bttg.). 



The type A. su'btilissima (pi. 5, fig. 11, after Sandberger) 

 is a minute shell less than 2 mm. long, with only microscopic 

 striae. While not uncommon, it is local. According to Boett- 

 ger, no trace of descent from older or relationship with 

 younger or recent land shells is known. Jooss has noticed 

 another species, still undescribed (Nachrbl. d. Mai. Ges., 44, 

 1912, p. 37). 



Acmopupa subtilissima, (Al. Br.). Bulimus subtilissimus 

 Al. Braun, in Walchner's Geognosie, 2d ed., p. 1137. Pupa s., 

 Sandberger, Vorwelt, p. 398, pi. 23, f. 13. Upper Oligocene 

 Landschneckenkalk von Hochheim. 



The figures of Wenz (Jahrb. Nassau. Ver. Nat., 1914, p. 93, 

 pi. 5, f. 14) show a more obtuse summit than Sandberger 's 

 figures. 



Genus NEGULUS Boettger. 



Negulus BTTG., Jahrb. Nassauischen Vereins fiir Natur- 

 kunde, Jahrg. 42, 1889, p. 268 ; type by original designation 

 Pupa, reinhardti Jickeli. 



"Shell perforate, either cylindric-ovate or oblong, pecu- 



