4 BULLETIN 91, UNITED STATES NATIONAL MUSEUM. 



Family TORNATINIDAE. 

 Genus ACTEOCINA Gray. 



ACTEOCINA SMITHI, new species. 

 Plate 1, fig. 9. 



Shell cylindric, semitransparent. Nuclear whorls small, well 

 rounded, smooth, forming a planorboid spire whose axis is at right 

 angles to that of the succeeding turns. The nucleus surmounts the 

 fairly well elevated spire formed by the succeeding turns. Post- 

 nuclear whorls, five, cylindric, slightly contracted in the middle; 

 gently rounded anteriorly and more abruptly at the summit. The 

 parietal wall is covered by a thick callus which extends posteriorly on 

 the preceding whorl, a little higher than the outer wall of the last 

 whorl, with which it is united by a U-shaped bridge, that joins the outer 

 wall so as to form an exceedingly acute ridge ; a deep channel therefore 

 separates the outer from the parietal summit on the last whorl. 



Entire surface marked by very regularly spaced, fine, raised axial 

 threads, that are separated by spaces about as wide as the threads. 

 These threads curve strongly posteriorly in the middle. In addi- 

 tion to the axial sculpture, the basal half of the shell is marked by 

 fine spiral striations which are best developed near the base. 



Aperture reversed comma-shaped, posterior half of about equal 

 width, anterior half expanding gradually from the middle of the 

 wall; outer lip thin, curved; parietal wall covered by a thick callus 

 which is continuous with and reflected over the columella. The 

 columella joins the outer Up in an even curve. 



There are two specimens, cotypes, in the collection, from Port 

 Alfred, Cat. No. 186657, U.S.N.M. (Coll. No. 12) . One, an adult some- 

 what rubbed, the other a young perfect individual. The first 

 measures: Length, 4.5 mm.; diameter, 2.0 mm. The latter: Length, 

 3.5 mm.; diameter, 1.7 mm. 



These specimens were sent to us by Col. Turton under the name of 

 Tornatina voluta Quoy and Gaimard. It is possible that this is the 

 species that has been reported from Port Alfred under that name. 

 It is not T. voluta Quoy and Gaimard. That species, which was 

 originally described from Guam, 1 is much larger, length, 10.5 mm.; 

 diameter, 4.2 mm., and is said to be smooth. 



ACTEOCINA, species? 



Cat. No. 250577, U.S.N.M., contains a young specimen belonging to 

 this genus, from Port Alfred (Coll. No. 1450). 



Genus RETUSA Brown. 



RETUSA TRUNCATULA Bruguiere. 



Cat. No. 186659, U.S.N.M., six specimens from Port Alfred (Coll. 

 No. 14). 



1 Voyage de I' Astrolabe, p. 359, pi. 26, figs. 33-35, 1832. 



