CEPHALOPODA OF THE ORETACEOCTS MARLS. 263 



an abruptly increased vertical height to the neck or straight part to the 

 base of the aperture; the line of which is exactly rectangular to it, and 

 slightly infolded on the edge; surface of the shell marked throughout by 

 transverse undulations, small on the inner coils and frequently bifurcating, 

 but directed straight across the shell from the ventral line. On the hori- 

 zontal portion they are much stronger and coarser, and above the outer 

 geniculation they again become as fine and close as on the inner coils. 

 The shell is further ornamented by two lines of nodes along the sides ; the 

 outer lines the smallest on the outer chamber, the other line imperceptible 

 on the coiled part. At the angle of the outer geniculation there exists the 

 largest node of all and outside of it two or three smaller ones. Septa 

 somewhat closely arranged, but rather simple in structure, composed of a 

 dorsal and three lateral lobes; dorsal lobe with four divisions, two on each 

 side of the central line, the first division doubly clavate, the other with 

 four rounded projections on the outer side; second lobe, or first lateral lobe, 

 with two main divisions widely separated, each of which is deeply bifur- 

 cate, with slight lobations near their extremities; second lateral lobe small, 

 clavate with a trilobed end; third lateral lobe only about half the size of 

 the second, but of similar form; first sinus much wider and larger than the 

 first lateral lobe, with four double divisions (one of which in the septum 

 drawn is imperfect); second sinus with two double or bilobed divisions; 

 third sinus simply bilobed, and the third simple; the septum figured and 

 its details here given is the second from the outer chamber of Dr. Morton's 

 figured specimen and gives the details of course much more developed than 

 would a septum at an earlier stage of growth. 



Dr. De Kay described this species originally from an imperfect cast of 

 the outer chamber of only medium size, which appears to have been the 

 property of the New York Lyceum, and was from Delaware. I have 

 before me at the present time a similar specimen of somewhat smaller size, 

 having only about half the diameter of the one figured, but showing the 

 same features on a reduced scale. The species is peculiar among all the 

 American Scaphites in the rapid lateral increase in size of the central por- 

 tions of the outer volution, which gives it a peculiar form and appearance 

 which will readily distinguish it. 



