

PLATE X. 



Aster, stellare. 1 Fig. 1, 2, drawn from a sketch of a specimen in the Museum of Stutt- 

 gardt, 450 mm. in diameter, showing extreme modifications in old age, loc. Goppingen. 



Aster, acceleratum. Fig. 3, drawn from sketch of specimen in Museum of Stuttgardt, 

 258 mm. in diameter, showing premature senility, loc. Balingen. 



Oxyn. oxynotum. Fig. 4, 5, young of striaries-like variety, magnified twelve times, loc. 

 Balingen. 



Ast. impendens. Fig. 6, young magnified four diameters. Fig. 7, abdominal view of 

 same, showing the early age at which the convergent sides, deep channels, and prominent keel 

 are developed. Fig. 8, 9, older stage of same specimens. Loc. Senmr. 



Aster. Collenoti. 2 Fig. 10, full-grown specimen, natural size, showing ribbed young, loc. 

 Champlony, near Semur. 



Agass. Scipionianum. 3 Fig. 11, 12, var. spinaries of Quenstedt, loc. Gmiind. Fig. 13, 

 older specimen of same variety, with more compressed whorls and less prominent tubercles, loc. 

 Semur. 



Oxyn. oxynotum. Fig. 14, abdominal view of young with part of whorl removed, mag- 

 nified three diameters. Fig. 15, same specimen when whole. Loc. Balingen. Fig. 16, young 

 with prominent pilse and keel, loc. Gloucester. Fig. 17, young in the Museum of Stuttgardt, 

 -'howing absence of the keel until a late stage of growth, and exhibiting similarity to the 

 .au.« of Jgass. hvvigatum andstriaries. Fig. 17 a, suture of same enlarged. Fig. 18, ordinary 

 aspect of the young. Fig. 19, pathological case with crenulated abdomen, like the ynargaritatus 

 forms. Fig. 20, young of a variety, with folds on the abdomen. Loc. Balingen. Fig. 21, 22, 

 adult, loc. Salins. 



Oxyn. Lotharingum. Fig. 23-26, showing solid keel in young, hollow keel in adult, 

 and partly obsolescent keel in old age of specimen in Museum at Semur. 



Oxyn. oxynotum. Fig. 27, showing hollow keel filled with layers of shell in specimen at 

 Museum of Semur. 



Oxyn. Guibali. Fig. 28, 29, 31. drawn from sketch of specimen in the Museum of Semur, 

 showing solid keel in young, hollow keel in adult, and absence of keel in old age. 



Oxyn. Greenoughi. Fig. 30, enlarged perfect specimen of hollow keel in adult, loc 

 Stuttgardt. 



1 See Plate IX. Fig. 2, 3. * Se e Plate IX. Fig. 10, 11. 



3 See Plate VII. Fig. 11-15. 



