INVERTEBRATES. 393 



Septa rather crowded and deeply sinuous ; dorsal lobe large, 

 considerably wider than long, profoundly divided into two 

 large lanceolate branches, each of which has an acutely pointed 

 extremity ; dorsal saddle linguiforra, slightly oblique, a little 

 larger than the divisions of the dorsal lobe, and longer than 

 wide; superior lateral lobe conical or short lanceolate, as long 

 as the dorsal saddle, but not more than half as wide, and 

 acutely pointed at the apex; lateral saddle a little shorter than 

 the dorsal saddle, but narrower at the extremity; inferior 

 lateral lobe rather shorter than the superior, particularly on 

 the ventral side, but resembling it in other respects ; ventral 

 saddle shorter than the others, and broadly rounded. 



So far as we have been able to compare this fine species with figures and 

 descriptions of those described from foreign localities, or from American rocks, 

 it seems not to be very closely allied to any other form with which we are 

 acquainted. It evidently attains a large size, the specimen figured by us con- 

 sisting entirely of septate whorls. Length, or greatest diameter, about 4.20 

 inches ; height, about 3.42 inches ; breadth or convexity near the aperture, a 

 little over 1 inch. 



Should it be ascertained that the type of Montfort's proposed genus Aga- 

 nides, was a true Goniatite, then the names of this and preceding species would 

 become Aganides globulosus and A. iowensis. 



Locality and position : Alpine, Iowa; Coal Measures. 



ARTIOULATA. 



CRUSTACEA. 



ENTOM S TR AC A. 



XIPHOSURA. 



Genus BELLINURUS, Koenig. 



(Icones Sectiles, 18 — , iii, p. 230.) 



Not having had an opportunity to consult Kcenig's original diagnosis of this 

 genus, nor indeed a good description of it by any other author, we are not 



50 Oot. 1,1886. 



