ANIMAL TO ITS SHELL IN SOME FOSSIL CEPHALOPODA. 113 



Hecticoceras hecticuni, Reinecke, sp. (p. 98). 



Fig. 5. Left lateral aspect, x if . 



6. Right lateral aspect of same. x %. 



7. Ventral aspect of portion of same. X i'. 



Distichoceras Baiigieri, d'Orbiguy, sp. (p. 100). 

 Fig. 8. Right lateral aspect, x j. 



CEcotraustes crenatus, Bruguiere, sp. (p. 99). 

 Fig. 9. Right lateral aspect. X f. 



Arietites raricostatus , Zieten, sp. (p. 94). 

 Fig. 10. Left lateral aspect of entire specimen. 



11. Dorsal aspect of the portion ab, which is a natural internal cast of part of the body-chamber 

 showing at the base the remains of the two muscular scars. 



Sonn'uiia sp. (p. 98) . 



Fig. 12. Left lateral aspect, exhibiting the muscular scar on the inner portion of the outer whorl 

 opposite the arrow, and also the adjacent indentations. 



Clymenia undulata, Miinster (p. 105.) 

 Fig. 13. Right lateral aspect. 



14. Peripheral aspect of the same. 



Glyphioceras crenistria, J. Phillips, sp. (p. lOG). 



Fig. 15. Left lateral aspect. The fine white line opposite the arrow is the boundary of the annulus ; 

 the subtriangular patch into which it passes near the umbilicus is the left muscular sear, 

 the black line posterior to it is the edge of the last septum, the lighter portion near it being 

 the broken edge of the test. 



16. Front view of the same, the arrow pointing to the line indicating the annulus. 



17. Left lateral aspect of another example. The anterior septum is the base of the body-chamber. 



The muscular scar is indicated by the light patch (opposite the arrow) on the piece of the 

 test, one layer of which is part of the floor of the body-chamber. 



18. View of same from above ; the raised line on the piece of test wliicli is part of the floor of 



the body-chamber being indicated by the white line marked a. 



Glyphioceras tnmcatum, J. Phillips, sp. (p. 108). 

 Fig. 19. Left lateral aspect. X j. 



