CEPHALOPODA. 299 



annulations are distant from each other five mm. At a diameter of ten mm. 

 the annulations are distant about 2.5 mm. Surface marked by numerous fine, 

 evenly-rounded, interrupted, longitudinal strife ; crossed by finer, irregular, 

 transverse striae, and laniellose lines of growth. The longitudinal striae are 

 interrupted by the margins of the lamellose lines of growth, and often run 

 in lines oblique to the axis of the tube. 



Tbe internal mould shows the annulations somewhat rounded, and pre- 

 serves the transverse, lamellose striae. 



A large fragment has twelve annulations in the length of sixty -five mm. 

 A smaller fragment has eleven annulations, with a length of twenty-seven 

 mm., and diameters of nine and ten mm. respectively, at the two extremities. 



This species is characterized by its surface ornamentation and the frequency 

 of its annulations, in which it is distinguished from 0. crotalum and O. nantium. 

 The annulations are less frequent and less abrupt than in O. lima. From 0. 

 crotalum it further differs in the small apical angle, and less prominent and 

 more rounded annulations. The surface-markings resemble those in 0. lima, 

 but the number and character of the annulations is quite distinctive. 



Formation and localities. From the shales of the Hamilton group, at Mutton- 

 ville, Ontario county, and Moravia, Cayuga county, N. Y. 



Orthoceras nuntium. 



I'l.ATl.s xr.m, FIO& 4 10, It, 14; I.XXXII, FIGS. 14, 15. 



OrtkoetraM nuntium. Hall. Descriptions of New Species of Fossils, etc., p. 51. 1861. 



Fifteenth Rep. State Cab. Nat. Hist., p. 79, pi. 8, figs. 3, 4. 1862. 

 " " " Illustrations of Devonian Fossils : Cephalopoda. Explan. of pi. 43. 1876. 



Shell straight, regularly and rapidly enlarging from the apex. Transverse 

 section subcircular. Apical angle about 9°. Initial extremity unknown. 



Chamber of habitation not fully observed. Air-chambers regular, numer- 

 ous, having a depth of two mm. where the tube has a diameter of ten mm., 

 and are of about the same frequency as the annulations. 



