JTjC) guide to the EOSSIIj INV]CUTEJJHATE animals. 
Gallery 
VII. 
Table-ease 
1 . 
SpiriUirosti-a tlie apex of the chambered shell is coiled (piite 
round, and a part of tlie sheatli lias come to lie above it; the 
rest of the sheath is <4reatly reduced and ends in a sharp 
point. r>y further coiling of the shell, by reduction of the 
pro-ostracum, and by the linal disappearance of the guard, 
was ])roduce(l the coiled shell of Spinda (Fig. 80 c). This is 
very like a .shell of the earlier coiled 7 \mmonoidea, but the 
si[)huucle is on the inner side of the coil, the septal necks 
Fici. 8G. — Cophalopods with thin enclosed shell. a, Bclemnolcuthis 
antiqua, Oxford clay, Wiltshire ; showing phragmocone (pli), ink- 
sack (t), folds of mantle (>»), one of the eyes (o), and the short arms (a) 
with their hooks (h) ; One-third natural size, b, Doratcuthis syriaca, 
Cretaceous, Lebanon ; showing shell and ink-sack as though the 
enclosing mantle were transparent; nat. size. 
pass backwards, and the shell is veiy thin. It is almost 
entirely enclo,sed by the mantle. 
iMeanwhile a distinct line of evolution was progressing. 
Among the beautifully preserved fossils of the Oxford Clay 
of Christian IMalford is the specimen of Bdnmwtc'idMs 
antiqua described by G. A. Mantell (Fig. 86(f). Here are t(» 
be seen 10 short hook-bearing arms, the head Avith its well- 
developed eyes, the folds of the mantle, the tin.®, the ink-bag. 
