SUPPLEMENT. 
335 
Dr. Lindstrom observes that “ the truncated end appears in all 
cases to have been strengthened from within by fresh linings of 
shelly material, and the animal continued to secrete its shell until 
the Ascoceras portion was formed.’’ It is further stated that 
Fig. 51. 
Ascoceras, showing the Orthoceras- and Ascoceras-stage ; after Lindstrom. 
“broken off stumps of the former stage have been 
found, which can be matched to five of the nine Gothland species 
of Ascoceras. They all show the characteristic peculiarities of a 
narrow thin shell, very gradually increasing in width, oval or ellip- 
tical in transverse section, and ornamented by obliqiW, transverse 
striae. The body- chamber is extraordinarily long, the intervals 
between the septa, at first short and irregular, became, during the 
progress of the growth, unusually long. The siphuncle is narrow 
and straight, generally situated near the ventral surface. The de- 
collation is oblique, following the direction of the septa. 
“ The commencement of the Ascoceras-atage is partially indicated 
by the increased distance between the septa.” Dr. Lindstrom 
’ Dr. Lindstrom calls this the “ Nautilus" stage. 
