PLATE IV. 
Cor. lyra.! Fig. 1, young of variety with broad abdomen and closely arranged pile. 
Fig. 2, young of var. B, with narrower abdomen and rounded sides. Fig. 3, older stage of same 
variety. Fig. 4, 5, nearly full-grown stage of same variety. Loc. Semur. Fig. 6, 7, full-grown 
stage of variety with narrower abdomen, flattened sides, and closely arranged pile, figure 
reduced to about one half, loc. Filder. Fig. 8, young of same variety as Fig. 1, but transitional 
to var. B. Fig. 9-11, young of var. C. Fig. 11a, suture of same. Fig. 12-14, young of variety 
like Fig. 1, 1 a, and Fig. 8, but with narrower abdomen and more flattened sides. Loe. Semur. 
Fig. 15, 16, cld specimen of var. C, with very convergent sides, and tubercles considerably 
reduced, diameter 250 mm., loc. Gmiind. Tig. 17, sutures on the inner side (dorsum),? loc. 
Semur. 4 
1 See Plate V. Fig. 1-3. 2 All the specimens figured were casts. 
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