RETUSA. 229 



tusely plicate; external-basal angle of aperture very prominent ; lip 

 thin, contracted in the middle. Alt. 3i, diam. 1 lines (Ph.). 



China (Largilliert). 



Bulla involuta PHIL., Zeitschr. f. Mai., 1851, p. 64. 



Has much affinity to B. convoluta Brocchi, but shorter, striated 

 above and below, and base of the aperture suddenly dilated (Ph.}. 

 The generic position is very doubtful. Perhaps it is a Cylichna. 



R. SEMINULUM Philippi. Unfigured. 



Shell small, subcylindrical, a little attenuated toward the base, 

 very smooth, milk-white; spire short, obtuse, distinct; aperture 

 linear, a little dilated at the base, obsoletely folded. Alt. H, diam. 

 I lines (PA.)- 



Manila. 



Bulla semmulum PHIL., Zeitschr. f. Mai., 1851, p. 64. 



This species is like B. obstricta Old., B. obtusa Mont , but differs 

 in having the base of the shell attenuated and the aperture much 

 narrower (Ph.). 



Subgenus PYRUNCULUS Pilsbry, 1894. 



Sao H. & A. ADAMS, Gen. Rec. Moll., ii, p. 21, Sept., 1854, type 

 S.pyriformis A. Ad. Conf. SMITH, Ann. Mag. Nat. Hist. (4), ix, p. 

 354, 1872. 



Not Sao Billberg, Enum. Ins., p. 135, 1820 (Crustacea*), nor Sao 

 Barrande, 1846 (Trilobita) ; nor Sao Kolliker, 1853 (Siphonophora, 

 forskaliides). 



Shell pyriform, \vide below, narrowed above, the aperture as long 

 as the shell, and of similar shape, columella thickened. Spire de- 

 pressed and rather shallowly or deeply umbilicated. Surface gen- 

 erally with some basal spiral strise. Soft parts unknown. 



Adams' name Sao being thrice preoccupied, has been changed to 

 Pyrunculus. The systematic position of the species cannot be defi- 

 nitely settled until the soft parts are known Adams considering 

 the group a subgenus of Atys, Smith placing it under Cylichna, 

 while Fischer has Sao as a subgenus of Tornatina. The characters 

 of the shells' apex seem more like Retusa than Cylichna, so that it 

 may be advisable to retain it as a section of that genus for the pres- 

 ent. 



R. PYRIFORMIS A. Adams. PL 33, fig. 68. 



Shell small, ovate, greatly dilated at the base, gibbose, shining, 

 white, smooth, pellucid, apex truncated, obsoletely longitudinally 

 16 



