66 
The centre whorles are very thin, and frequently lost, as in 
this specimen. 
The middle figure exhibits a cast of one of the chambers 
formerly distinguished by the name of Spondylithes; it 
shows the shape and principal undulations of the margin of 
the septum, with the hole of the siphunculus through it, 
and the protuberating undulations outside. 
When we have learned by some experience, that better 
are not to be obtained, imperfect specimens of organic 
remains must be used; they serve well to instruct us, and 
exhibit the internal organization, &c. 
The specimens were a little larger than the figure, and 
are filled with a brown stony marle; the shell being some- 
what like hardened chalk and yellowish, some are more 
decomposed, softer, and whiter or stained with ochre. 
They are found in the parish of Worlingham near Beccles, 
and are lent me by my friend, R. Sparrow, Esq. I have 
inferior specimens from other parts of Suffolk. 
