PLATE XCI. 



Orthockras Bkbrtx, var. Catuqa. " 



Page 276. 

 See Plates 39, 86, 92. * 



Rg. 1. A chambered ft^gment, showing' a gfradnal increase in the depth of the wr-chambere from the apex 

 toward the outer chamber. Jthaea, N. Y. 



Fig. 3. A large fragment somewhat compressed, showing an obliquity of the sutures, and an iri-egularity 

 in the enlargement of the tube, due to the compression. University Quarry, Ithaca, N. T. 



Fig. 3. A portion of a large individual, showing the cylindrical chamber of habitation, and a nearly uniform 

 distance between the septa. Earl's Quarry, Ithaca, Jf. T. 



Fig. 4. A small fragment showing the concavity of the septa. Earl's Quarry, Ithaca, N. T,- 



Fig. 5. A septum of the preceding, showing the position of the siphoncle, the effect and amount of the com- 

 pression. 



