88 F. B. Meek on Acteonide. 
org (Woodward), and the operculum probably wanting, (H. & A. 
ams). 
Secrion (a). Columella plaited. Section (b). Columella without plaits. 
7 Genus Ringicula, (Desh.) 
7 Genus Ringinella, (d’Orb.) 
7 Genus Bees pir (Gray) —-——_—— Genus Aptycha, (Meek). 
genus Avellana, (d’Orb.) . 
rs actoneed Euptycha, (Meek) 
? Genus Zylostoma, (Sharpe). 
In addition to the genera here ranged in the Actwonide, the 
genus Mucrocheilus of Phillips, which has been generally referred. 
to the Pyramidellide, probably also belongs to this family. If so, 
its position would appear to be intermediate, as it were, between 
sections (a) and (4), of the subfamily Actwonine : some of the » 
bed having rather distinct folds on the columella, others hav- 
g them very obscurely haa a me still others being en- 
rely destitute of such folds or plait D’Orbigny and several 
others also include the curious genus Pisicidiniy: ‘which certainly 
seems to be related to this group in some of its characters; but 
if included at all, it should stand apart, as the the type of a very 
distinct subfamily, on account of its dilated, Saatiiaetike lip, 
with a single internal tooth, as well as in consequence of the 
distinct anterior canal of some of the species. e Jurassic genus 
* These three are regarded by some authors as not being generically distinct, and 
even d'Orbigny, ater t propoapg she genus Ringinella, united it with Avellana, 
However difficult it may sometimes be to treat ie or still appear to repre- 
sent three generic hoon and shoal doubtless 
® The genus Tubifer, as established Sd oat in n 1856 (Bull. Geol. Soc. F: 
ser., vol, xii, p. 1083, pl. ‘31, and vol. xiii, p. 592), includes two rather distinct — 
er plicatus, of Piette, although s speci sally distinet, ‘t Baoon es necessary to 
od ave ew specific name, I would therefore propose to call it Tubifer (Costel- 
ifer) Zi 
pleeeny Tittle Jurassic shell, figured by Piette in the 13th vol. Bull. Geo 
cited eae (pl. xv) under the ‘provisional name Fasciolaria nuda, (previ . 
ferred b to Mitra), § seems to be closely related to the genus Soleniscus, 
& Wiithen & from the i roceed, Acad. : 
Oct., 1860, ps 467). It should either be ranged as a subgenus under Soleniscus, 
having three folds on the columella instead 0 of one), or regarded 
genus. 
