ASCOCEEATID^. 
251 
all adult individuals. The posterior, dilated part of the bod)— 
chamber occupies a little less than ^ of the total length of the shell. 
When the fossil is well preserved the test covers the whole of the 
truncated extremity ; nevertheless there are indications, in the shape 
of a groove surrounding the latter (fig. 43, gr), of the removal of 
one of the earlier chambers during the growth of the animal. A 
little tnhnlar projection marks the position of a siphuncular neck 
near the ventral margin (fig. 43, n). 
Fig. 43. 
Ascoceras Verneuili. — a, lateral view of a specimen, showing traces of the 
curved septa ; h, transverse section of the same taken at about the mid- 
length, the shaded part represents the body-chamber ; c, concave side of 
the same specimen, showing the truncated extremity ; d, view of the pos- 
terior extremity, showing the position of the siphuncle, and at gr the 
outline of the truncated portion ; e, concave side of another specimen, the 
septate part has been removed, leaving marks of the septa upon the cast (s) ; 
f, posterior extremity of the same specimen, showing the opening of the 
siphuncle upon the internal cast ; g, lateral xiew of the same individual, 
showing marks of the septa upon the cast (s) ; h, transverse section taken 
at mid-length, oriented to correspond with g. 
The surface of the test in this species is rarely preserved, and it 
thus appears to be devoid of any ornamentation ; there are, however. 
