FOSSIL CEPHALOPODS 77 
rian times. Some chambered Cephalopods known 
as Orthoceratites (Greek, orthos = straight, and keras = 
horn) existed in the Cambrian Period. As their 
name implies, they were straight, not coiled (see 
Fig. 25). Perhaps they stand as memorials of a very 
early stage in the development of the nautilus kind. 
It is quite likely that the animals found themselves 
clumsy in a straight position, and discovered it to be 
Hamites attenuatus (Cretaceous). 
Fig. 26.—ANCYLOCERAS AND HAMITES. 
Fossil Cephalopods. 
advantageous to coil themselves up. The coil may 
have been gradually developed through many ages of 
effort in that direction. Another ally of the nautilus 
was the Ancyloceras (Greek, ankylos =incurved), in 
which one end of the shell is loosely coiled, and the 
other curved inwards like a hook. Fossil remains of 
this animal are found in Cretaceous strata. Then 
there were other Cephalopods whose shells were 
