VALLONIIDAE. 173 



Bourguignat, but expressly claimed it himself. It is a Vertigo 

 (vol. 25, p. 201). 



Pupa orcutti Pilsbry was mentioned by C. K. Orcutt (West 

 American Scientist VII, Oct. 1891, p. 270) as from near San 

 Quentin Bay, Lower California, on lichens. It is a nude name. 

 I have no record or recollection of this species, but it was 

 probably one of those described later from the same region. 



Family VALLONIIDAE. 



Valloniidae Pilsbry, 1900, Proc. A. N. S., Phila., p. 564. 



Acanthinulinae Pilsbry, 1918, Man. Conch., vol. 24, p. x; 

 27, p. 186. 



AcanthinuUdae Steenberg, 1918, Vidensk. Medd. Dansk. 

 Naturh. Foren., vol. 60, p. 14. 



Valloniinae Watson, 1920, Proc. Malac. Soc. Lond., vol. 14, 

 p. 6. 



Minute orthurethrous snails with perforate or umbilicate 

 shells of few whorls, from discoidal to ovate-conic in form, 

 often with spaced cuticular ribs, and without internal laminae ; 

 the peristome either expanded, thickened or simple ; toothless 

 (except in Spelaeodiscus) . 



The oviparous or viviparous animal has a long penial ap- 

 pendix; the retractor muscle forked (except in Planogyra). 

 The prostate gland is short and posterior. As in many other 

 unrelated genera of minute orthurethous snails, the terminal 

 male organs are often wanting. The arcuate jaw is thin, with 

 weak, flat vertical folds. Central tooth somewhat or decidedly 

 narrower than the laterals, tricuspid or with ectocones much 

 reduced. Lateral teeth bicuspid ; marginal teeth wide, pectin- 

 ate, with several or numerous narrow cusps. 



This group is understood in the limits of Steenberg and 

 Watson except that the genera Pyramidula and Pleurodiscus 

 are excluded. 



The character of being toothless has not, I think, been suffi- 

 ciently appreciated by those who would unite Valloniidae with 

 the Pupillidae or the Strobilopsidae. Two leading genera, 

 Vallonia and Acanthinula, are known in many species from 



