LAMELLIBRAI^CHIATA OF THE LOWEE MAELS. 145 



those of that species being directed forward. There is a close resemblance 

 between this shell and the F. trigona Gabb. Indeed they might quite read- 

 ily be confounded, and may perhaps be identical; but the specimens referred 

 to the latter species never show anything of the undulations of the surface 

 so characteristic of V, Conradi It is possible, however, that as all of those 

 of V. trigona yet known are large, and have been much thickened shells, 

 that these features would not have been retained on the internal casts. This 

 fact might have been decided by an examination of the interior of Morton's 

 type, but I did not succeed in finding it in the collection at Philadelphia, 

 although Mr Meek appears to have had it in his hands, as he figures one in 

 the Invert. Pal. of the Territories, p. 148, which he refers to as Morton's 

 type, but which is much larger than Morton's figure. The shells described 

 by Mr. Conrad as F. inflata and F. elevata may be only small or dwarfed 

 specimens of this same species. They are, however, very ventricose, and 

 bear the imprint of adult age, but are otherwise very similar. The beaks of 

 both of those species are somewhat more erect and the posterior slope more 

 abrupt, but this would still be the case in small shells where the form was 

 similar to some of those which have been identified with this one without 

 question. 



Formation and localities, — The shell is present in the collections from 

 the State from the Lower Green Sand& at Holmdel, and from the mica- 

 ceous clays under the lower bed at the Rev. G. C. Schanck's pits, near 

 Marlborough, New Jersey. These show tlie strong undulations of the 

 exterior, and are comparatively small specimens, retaining but little of the 

 substance, being really external casts, and do not preserve any features of 

 the interior. 



Veniellia decisa. 



Plate XIX, Figs. 15 and 16. 



Cardita decisa Morton. Synopsis, p. 66^ PI. IX, Fig. 3. 



Venilia Conradi Gabb. Synopsis, pp. 104 and 130 (not of Morton). 



Shell of medium size, subquadrangular, rhomboidal or triangularly 

 rhombic in outline, dependent more or less on compression or distortion of 

 4418 MON 9 10 



