94 



MANUAL OF THE MOLLUSCA. 



Spi.^ orbiJites Lam. planulites, Montf. 



Shell, discoidal ; inner whirls more or less concealed ; septa midulated ; 

 sutures lobed and foliated ; siphuncle dorsal. 



Bistr., 530 sp. Trias— chalk. Coast of Chili (D'Orb.) Santa Fe de 

 Bogota (Hopkins), New Jersey, Europe, and S. India. 



Capt. Alexander Gerard discovered ammonites similar to our L. oolitic 

 species, in the high passes of the Himalaya, 16,200 feet above the sea. 

 Section A. Back, with an entire Jceel. 



1. Arietes, 



2. Falciferi, 



3. Cristati, 



4. Amalthei, 



5. Rhothomagenses, cret. 



C 

 oolitic, 



6. Disci., 



7. Dentati, 



8. Armati, 



9. Capricorni, 

 10. Ornati, 



L. oolites, A. bifi-ons (pi. III., fig. 6), bisulcatus (pi. 



in., fig. 7). 

 L. oolites, A. serpentiuus, radians, hecticus. 

 cretaceous, A. cristatus, rostratus (fig. 55), varians. 

 B. Back crenated. 



A. amaltheus, cordatus, excavatus. 

 A. rhothomagensis (pi. III., fig. 4). 

 Back sharp. 

 A. discus, clypeiformis. 

 Back channelled. 



ool. 



D. 



f cret. A. dentatus, lautus. 



\go1. a. Parkinsoni, anguliferus. 



E. Back squared. 



L. ool. A. armatus, athletus, peramiatus. 



L. ool. A. capricornus^ plauieostatus. 



ool. A. Dimcani, Jason (pi. III., fig. 5). 



^^r^^ty^' 



Fig. 56. Ammo?)ites coronatus.* 

 E. Back round, convex. 



11. Heterophi/lli, L. ool. 



12. Ligati, cret. 



13. Annulati, ool. 



14. Coronati, ool. 



15. Fimbriati, ool. 



A. heterophyUus (fig. 34). 

 A. planulatus (pi. III., fig. 3). 

 A. annulatus, biplex, giganteus. 

 A. coronatus (fig. 56), sublae\is. 

 A. fimbriatus, lineatus, hu-cinus. 



" Fig. 56. Profile of ammonites coronatus, Brug. (reduced ^ from D'Orbigny) 

 Kelloway rock, France, d I, dorsal lobe ; ss, dorsal saddles ; I' V . lateral lobes ; *'*'. 

 lateral saddles; accessory and ventral lobes. The number of accessory lobes increases 

 ■with age. 



