PLATE I. 
Psil. planorbe. Fig. 1, cast with incomplete living chamber, showing folds at an early 
stage of growth. Fig. 2, suture much enlarged. Loc. Whitby. Fig. 3, 4, cast with similar 
folds in the young, but smooth in the adult. Fig. 4a, young of Fig. 4 enlarged. Loc. Neuffen. 
Fig. 5, 6, cast of the more involute variety, loc. Balingen, The specimen has distorted sutures, 
showing the broad abdominal lobe and the large median saddle on one side, but is otherwise 
normally formed. 
Cal. Nodotianum. Fig. 7,} specimen reduced to less than one half, showing incomplete 
living chamber. Fig. 8, sutures enlarged. Fig. 9, a fragment of a cast showing sutures and. 
part of living chamber. Fig. 10, section of four whorls. Fig. 11, acast. Fig. 11a, section of 
last whorl. Loc. Semur. 
Cal. tortile. Fig. 12, specimen with portion of living chamber. Tig. 13, same, portions 
of the two outer whorls removed, showing their rounder outlines. Fig. 14, suture of same, 
enlarged. Joc. Semur. 
Cal. carusense.? Fig. 15, cast of the younger stages, broken out of the interior of an 
adult specimen, loc. Balingen. Fig. 16, cast, loc. St. Thibault. 
Verm. spiratissimum. Fig. 17, cast, living chamber incomplete, loc. Nellingen. Fig. 18, 
specimen with distinct channels, developed at an early age, loc. Semur. : 
Cal. sulcatum. Fig. 19, specimen with incomplete living chamber, showing the smooth 
young in the centre. Fig. 20, suture of the same, enlarged. Loc. Semur. 
Verm. ophioides. Fig. 21, cast of a broken specimen, showing the well developed chan- 
nels and keel in the young, and the early appearance of the pile. Figs. 22, 23, sutures of this 
and an older specimen, enlarged. Loc. Semur. 
Cal. raricostatum. Fig. 24, specimen, showing the senile metamorphoses. Fig. 25, 
section of last two whorls, showing the corresponding change of form for comparison with 
Fig. 25a, the adult of the same variety.’ Loc. Balingen. 
1 This figure is not numbered. 2 See Plate II. Fig. 1. 
8 See Plate VI. Fig. 15, for the Johnstoni-like variety. 
