NATURAL SCIENCES OF PHILADELPHIA. 



233 



almost horizontal. By fig. 11 of pi. XVII., representing V. Flori- 

 do.na, it will be seen that the teeth are of a very peculiar type. 



The lingual membrane is long and very broad, comprising (in 

 the Florida species) about 60 1 60 teeth. The centrals have 

 their base of attachment quite small, long and narrow, attenuated 

 to a point above, gradually enlarging toward the base, above which 

 are lateral, bluntly pointed, wing-like expansions ; the lower mar- 

 gin is broad, and has a deep, rounded excavation ; in some cases 

 the lateral expansions are so produced as to give an almost cruci- 

 form appearance to the base of attachment; below the centre of 

 the base of attachment, on its anterior surface, is a stout, blunt, 

 short, simple cusp, ending in a short, stout cutting point. 



Fig. 76. 



o$233353W^ 



Lingual dentitiou of Veronicella Floridana. 



The lateral teeth are very irregular in shape, but retain the bi- 

 cuspid character peculiar to the Geophila ; they are longer and 

 much wider than the centrals ; the bases of attachment are 

 very irregular in shape, very unsymmetrical, subquadrate or ir- 

 regularly excavated above, thence curve outwards and downwards, 

 until at their lower extremity they exhibit the lateral expansions 

 and basal excavation of the central tooth, but both these charac- 

 ters are much more developed than in the centrals, and from the 

 want of symmetry in the teeth, are found only on the outer side 

 of each tooth ; the upper edge is squarely reflected, the reflection 

 is very large, extends half way to the lower edge of the base of 

 attachment, and is produced beyond that into a blunt, stout cusp 

 bearing a stout cutting point ; the side cusps are almost obsolete, 

 the inner one is much larger than the outer one, neither with dis- 

 tinct cutting point. The marginal teeth are a simple modification 

 of the laterals, being reduced to a subquadrate shape, with the 

 cutting point of the cusp much more produced. 



I give on pi. XVI., fig. 11, a group of centrals and laterals in a, 

 a marginal in b. 



I have not been able to examine V. olivacea, the only other 

 species found within our limits. 

 16 



