F’. B. Meek on Acteonide. 89 
somewhat doubtful. Some of the species have the surface striate 
or punctostriate, as is usual in that group, and the outer lip 
thickened, but only at intervals, so as to leave varices on the 
yolutions; while between these it was probably always thin dur- 
ing the growth of the shell. In its other characters this genus 
to define some of the allied groups which it is proposed to 
restrict. The following descriptions are therefore offered :— 
Subfamily ACTAONIN A. 
SEcTION a, 
Genus ACTAONELLA, d’Orbigny. (As restricted.) 
Shell ovate-volvuliform, rather thick, involute, more or less attenuate 
above, widest below the middle,—entirely without any traces of a spire. 
Surface nearly smooth. Aperture very narrow, arcuate, and equalling 
the greatest length of the shell. Outer lip smooth, generally rather ob- 
tuse, Inner lip thickened near the base of the aperture, and twisted out- 
Wards so as to form on the columella three prominent revolving folds; 
also usually a little thickened at the summit of the aperture. 
Type :—Volvaria levis, Sowerby,’ (= Acteonella, d’Orb.). Also in- 
cludes Volvaria crassa, Dujardin, (= Actewonella, d’Orb.); Acteonella Cau- 
castca, Zekeli, A. Syrica, Con., and A. Dolium, Reem. (A!I Cretaceous.)"® 
Genus TROCHACTZON, Meek, (Acteonella, (part) d’Orb.). 
ee turbinate, rather thick; the widest part always above the middle 
the body-whorl. Last turn large, rounding in above, and tapering 
cma tie oes 3 
oa of the -whorl, or even sunken so as to form an umbilicoid cavity ; 
ti “0 prominent, with sides generally coneave in outline. Suture som 
ae channel Surface nearly smooth. Aperture very narrow and 
"8: generally subangular or narrowly rounded below. Outer lip sharp 
Smoot; in. Inner lip thic w, and twisted into 
three folds, which continue around the columella wer the a 
‘ : : oe 
ica, “4 —Acteonel sprees arama 
Conus GYlandiformis, and A, rotundatus, Zekeli; A. gigantea, d’Orbigny, 
}} Cylindrites pyriformis 
* ‘Trans. Geol. Soc. Lond., vol. iii, pl. 39, fig. 33. 
*” Excepting A. Syriaca which is sup’ to be Jurassic. " 
_™ Paleont. Franc. Terr. Cret., vol. 2, p. 108, pl. 164, fig. 7. 
Ax. Jour, Scl.—Suconp Series, Vou. XXXV, No. 103.—Jan., 1863. 
12 
