RI a 
L. Agassiz on the Ichthyological Fauna of Western America. 217 
towards the centre, but occupy near it a broader field than usu- 
ally and diverge towards the posterior margin in such a manner 
that the concentric ornamental ridges of the lateral fields and of 
the anterior field are not intersected by them. 
The pharyngeal teeth are arranged in two rows, the outer one 
with four somewhat compressed teeth, curved inwards, termina- 
ting with a small hook and provided with a small grinding sur- 
face upon the inner margin. The inner row has only a single 
tooth, more conical than the outer ones and much smaller. The 
msertion of these teeth lower 
upon the branch of the sym- 
physis than usually is also 
quite characteristic. 
sum maxillingua, 5, ¢ and d, 
the lougest tooth of the outer 
row from three sides and e, 
the smallest in profile. 
Pygmeus, Fundulus fuscus and Hydrargyra fusca. 
All these descriptions relate only to two species of one and 
the same genus, which however belongs neither to the family 
of Cyprinoids, nor to that of Cyprinodonts 1n which the inter- 
maxillaries form the whole margin of the upper Jaw, but con. 
* j : i e Leuciscus pygmeus of 
DeKay fees eee no dae tenibad Road el of New 
York, without whi would hardly ae ee even the identity of 
a 
that fish with DeKay’s own Hy 
_ Skconp Serres, Vol. XIX, No. 56.—March, 3855, 28 
Pa 
