199 
SERJPULA ampullacea. 
TAB. DXCVII. —Jigs. 1. 2. 3. 4. & 5. 
Spec. Char. Thick, irregular, antiquated, with a 
globose enlargement near the entire aperture ; 
more or less carinated upon the back ; surface 
of attachment expanded, thickened. 
Kentish Chalk Fossil, a Serpulite. Parkinson , 3. 
94. pL 7 ./. 11. 
A large thick species, varying in form according to the 
surface to which it fixed, often choosing a thin cylindrical 
substance, when it becomes discoid, with a perforation in 
the centre (figs. 2. 3. 4. & 5.). It has sometimes a carina 
extending its whole length (as in figs. 2. & 5.), sometimes 
only for a part of it (as in fig. 4.), and at other times 
scarcely to be discovered (figs. 1. & 3.). The surface is 
often marked with small undulating lines, that give it in 
parts a granulated appearance (figs. 1.4. & 5.); other 
specimens are smooth (figs. 2. & 3.). All these varieties, 
when full grown, are considerably thickened before the 
aperture is finished ; so that the extremity appears to be 
inflated, but the inside remains cylindrical. 
Not unfrequent in Chalk, although hitherto almost un- 
noticed. All our figures are from the Norwich Chalk. 
No. 2. was presented to us by Mr. Barnes of Norwich ; the 
others belong to the Rev. G. R. Leathes, whose favours 
we have so frequently had to acknowledge. We have a 
specimen from Northfleet resembling in form Mr. Parkin- 
son’s : it is to be distinguished from Vermetus by the sur- 
face of attachment which occupies one side of the disk and 
a great part of the tube beyond it. 
