Cephalopoda of the Cincinnati Group. 



129 



.he greatest diameter of the siphuncle is about one and three fourth.^ 

 the distance between the septa; Avhile the septa are pierced with 

 holes about one half the diameter of the siphuncle. Body chamber 

 and outer shell unknown. 



Found on the hills back of Cincinnati ; range unknown. 



The septa are closer together, and consequently the chambers thinner 

 in this 'species than they are in any other known to me in the Cin- 

 cinnati Group. The rapid enlargement of the siphuncle in each 

 chamber is also a noticeable feature. 



The specific name is given in honor of my paleontological friend. 

 Prof. G. W. Harper, of Woodward High School. 



Orthoceras transversa — (S. A. Miller).. 



Fig. lb.— Orthoceras transversa, showing exterior markings of the shell and curvature of septs- 

 Shell medium size, rather rapidly enlarging ; septa strongly arched 

 and distant about one fourth or one fifth the diameter of the shell ; 

 siphuncle excentric, its form not observed ; outer shell thin and marked 

 by strong transverse lines, distant from 1-lOOth to 4-lOOths of an inch, 

 in a specimen having a diameter at the large end of three fourths of an 

 inch. The distance between these lines seems to increase as the 

 diameter of the shell increases, but their distance apart is not uniform 

 in different specimens of the same size. About four or five of these 

 transverse lines will mark the distance between the septa, though they 

 do not seem to have any connection with the arrangement of the latter.. 

 This is the only species, except one, known to me in the Cincinnati 

 Group marked on the outer shell with transverse lines. And it is a 

 curious fact, that while with all other species we usually find the 

 chambers and interior part of the shell, and rarely discover the outer 

 shell, yet, with this species it is just the reverse. We usually find the 

 outer shell or a cast marked Avith transverse lines, and rarely find it in 

 condition to show the chambers or the siphuncle. 



Its range, so far as I know, does not extend over 300 feet above low 

 water-mark. I found it in the excavation for Columbia avenue, at 150 

 feet above low water-mark, and at Eden Park, 200 feet above low water- 

 mark. It is not common by any means. 



