612 Contributions to Invertebrate Palaeontology. 



PLATE VII. 



Orthoceras nuntium Hall. Page 526. 



Fig. 1. View of a large individual of this species from the white cherty layers 

 of the formation near Dublin, Ohio, showing the general features 

 of the shell, the figure being cut to accommodate the length of tlie 

 plate. The lower portion of the short section represents the form 

 of the septum at about that position, the shell having been broken 

 near that point. 



Fig. 2. Enlargement of the surface from the lower part of the shell. 



Maceocheilus priscus Whitf. Page 525. 



Figs. 3 and 4. View of the aperture showing the straight columella, slightly 

 imperfect at the lower end, and a back view of the same specimen, 

 both enlarged to two diameters. 



LoxoKEMA PARvcLDM Whitf. Page 526. 

 Fig. 5. A view of a very perfect specimen enlarged four times. 



Platyceras squalodens Whitf. Page 524. 



Figs. 6-8. Lateral and vertical views of the specimen described, the later 

 showing the form of the base. 



GoMPHOCERAS AMPHORA Whitf. Page 530. 



Fig. 9. View of the upper part of a specimen showing the deep sinus of the 

 aperture, and the crowding of the septa in the upper part. 



Dentaliom Martini Whitf. Page 524. 



Fig. 10. View of a specimen retaining the shell and preserving nearly the 

 entire length. 



PLATE VIII. 



GoMPHOCERAs ? Hyatti Whitf. Page 529. 

 See also Plate IX. 



Fig. 1. Side view of an imperfect specimen showing the rapid contraction of 

 the dorsal side toward tlie aperture. 



Cyrtoceras cretaceum Whitf. Page 531. 



Fig. 2. Dorsal view of an imperfect specimen, slightly restored in the outer 

 chamber, showing the siphuncle in the lower part. The lirations 

 on the lower part are produced by the advancing scars of muscular 

 impressions. 



Fig. 3. Side view of another individual, a part of the separate portion removed 

 to show the siphuncle. 



