CLASS GASTROPODA 
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parum sinuato, haud canaliculato, suturam versus satis rotundato; labio 
distincto, postice subcalloso; columella plica satis exstante, axi basim 
circumgyrante. Long., .11; lat., .055 poll. (Carpenter.) 
On n’a trouve qu’un seul echantillon de cette petite espece, qui est 
intermediare entre les Cylichna et les Tornatina. (Carpenter.) 
Shell small, cylindrical, subelongate, white, smooth, covered with a 
straw-colored epidermis; margins nearly parallel; spire flat, hardly um- 
bilicated, slightly mammillate. Whorls 4, convoluted, sutures little im¬ 
pressed ; base moderately effuse; lip thin, rather produced in the middle, 
broadly arcuate in front, a little sinuous behind, scarcely channeled; toward 
the sutures quite rounded. Inner lip distinct, somewhat calloused behind; 
columella with quite a marked fold, the axis revolving around the base. 
Alt., .11; diameter, .055 in. (Tryon and Pilsbry, Manual of Conchology.) 
Type in? Type locality, San Diego, California. 
Range. Known only from type locality. 
Acteocina magdalenensis Dali, 1919 
Plate 2, figs. 2a, b 
Proceedings of the United States National Museum, 56:296. 
Shell small, slender, subcylindric, translucent white, polished, with 
four whorls, the nucleus minute, subglobular, transparent; suture distinct, 
more or less channeled, spire short but distinctly turreted, aperture nar¬ 
row, outer lip straight, rounding below into the thickened pillar which has 
a strong plait with a groove behind it, the body with a slight glaze. Length, 
6.7; diameter, 2.5 mm. (Dali.) 
Type in United States National Museum, No. 21841. Type locality, 
Magdalena Bay, Lower California. 
Range. Southern California to Magdalena Bay, Lower California. 
A new name for Acteocina infrequens Carpenter, not of C. B. Adams. 
Genus RETUSA Brown, 1827 
Shell small, subcylindrical, imperforate, with slightly raised flat, or 
depressed spire, the aperture as long, or nearly as long, as the shell, nar¬ 
row above, dilated below. Columella thickened, with a small fold or none. 
The species of this genus might be distributed into two groups, as 
Fischer has done. Part of them have a distinct fold on the columella. 
The other species have no distinct columellar fold, although the pillar-lip 
is thickened; and these fall into Utriculus as understood by Sars, Fischer, 
Dali, and others. (Tryon and Pilsbry, Manual of Conchology.) 
Type. Bulla truncatula Bruguiere, 1772. 
Distribution. Mediterranean, United States, Britain, North Atlantic. 
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