201 
SERPULA Plexus. 
TAB. DXCV1II .—Jig. 1. 
Spec. Char. Cylindrical,, smooth, very much 
curved, entangled into dense masses ; dia- 
meter about half a line, diminishing very 
slowly from the aperture. 
A common species that occurs in compact masses in 
Chalk. We have it from Norfolk and Sussex. The 
masses are sometimes as large as one’s fist, and com- 
posed wholly of numerous individuals of the same spe- 
cies. 
SERPULA Carinella. 
TAB. DXCVIII.— /g. 2. 
Spec. Char. Cylindrical, gradually tapering to- 
wards the apex, repent ; with a minute carina 
upon the back gradually lost towards the aper- 
ture. 
Nearly a line in diameter, moderately tortuose and 
partially raised from the substance upon which it creeps. 
Occurs in the Greensand. Our figure is taken from a 
Blackdown specimen, in which the shells are replaced by 
silex ; they are fixed inside a Venus. 
SERPULA compressa. 
TAB. DXCVIIL— /g. 3. 
Spec. Char. Lanceolate, rather compressed, 
smooth ; slightly tortuose ; aperture elliptical. 
Largest diameter four lines, rapidly diminishing ; a 
large part of the tube is free. 
From the great Limestone Strata which traverse in a 
northerly direction the county of Linlithgow, and consti- 
tute the independent Coal formation of the Lothians. 
Presented by the Rev. John Fleming, D.D. in 1814. 
