| 
| 
| 
| 
PLATE  V. 
Cor. lyra.’ Fig. 1-3, half-grown shell of same variety as Fig. 6, 7, Plate IV., showing how 
narrow the abdomen is in some specimens before the shell was full grown. Fig. 3a, suture, 
slightly older than that delineated on Fig. 2, showing the changes which had taken place. Loc. 
Semur. 
Cor. Gmuendense.’ Fig. 4, half-grown specimen, exhibiting variety with discoidal form 
and compressed whorls, figure reduced to less than one half. Fig. 5, full-grown specimen of 
same variety with marks of approaching old age upon the last whorl, figure reduced to less than 
one half. Loc. Semur. Fig. 6, specimen in which the wider abdomen and young proportion of 
Fig. 4 were maintained until a much later stage than in Fig. 4 or 5, figure reduced to about one 
half. Fig. 7, umbilicus of Fig. 6, about natural size, to show the smoothness of the young 
whorls, Loc. Aargau. Fig. 8, 9, same variety as Fig. 5, but showing the effects of senile 
decline in the convergence of the sides, degeneration of the pile and tubercles, diameter 
205 mm., loc. Semur. 
' See Plate IV. 2 See Plate VI. 
