FROM THE TERTIARY OF VIRGINTA. 233 
FAMILY SERPULIDA. 
GENUS SERPULA. 
S. convoLuTa, Pur. 34. Fia. 1. 
S. testa in spiram discoidalem contortd, ten, plerumque cancellatd, apud apicem regulariter volutd; aperturd rotunda. 
Shell twisted into a discoidal spire, thin, usually cancellate, regularly whorled near the apex; mouth round. 
Diam. .10 of an inch. 
Remarks.—This shell is generally twisted into a regular disc. The sculpture is very 
variable, sometimes seeming like longitudinal moniliferous coste, and, at others, regu- 
larly cancellate. The apex is singularly formed, being smooth and perfectly voluted, 
like a young Turbo. ‘This is, I suppose, the form it has when excluded from the egg. 
S. ANGUINA, Pi. 34. Fic. 2. 
S. tesid minima, irregulariter contortd, striatd, crassa; striis irregularibus transversis; apertura rotunda. 
Shell very small, irregularly twisted, striate, thick; striw irregular, transverse; mouth round.. 
Diam, .04 of an inch. 
Remarks.—This is a very minute species, and is, I believe, the only one of our fossil 
Serpule that has no longitudinal lines on the surface. This character will readily dis- 
tinguish it from others. The apex has the same voluted character as the last, although 
not as well developed. 
Genus Pretanoconcnus,* (Nosts.) 
Testa tubularis, solida, trregulariter contorta, laminis longitudinalibus duabus internis. 
Shell tubular, solid, irregularly twisted, with two internal longitudinal plates. 
Remarks.—The singular shell, on which I propose to found the above genus, differs 
from all the known tubular shells that I have met with, in the two internal longitudinal 
plates. It may possibly belong to the family Scalaride, and, if so, presents a link be- 
tween them and the Plicacide. 
P. scunpruratus, Pi. 34, Fie. 3. 
P. testd vel contorid vel turritd, crassd, costulis longitudinalibus noduliferis ; laminis internis politis, levibus, ad aper- 
turam obsoletis; apertura rotunda, 
Shell sometimes twisted, sometimes turrited, thick, with small longitudinal noduliferous ribs; internal lamine 
smooth, polished, obsolete at the mouth; mouth round. 
Diam. .20 of an inch. 
Remarks.—The longitudinal coste are generally nodulous, but they occasionally seem 
rather to be cancellated by transverse sulci, which, in other specimens, appear to usurp 
their place. ‘The two internal laminew are placed at about one-sixth of the circumference 
apart. They are generally directed towards the centre, and sometimes nearly meet. In 
some specimens they are much smaller than in others. They rarely or never seem to 
be continued to the aperture. 
This is a very variable shell, both as to the sculpture and internal plates. I at first 
* A wétaror, lamina, et xdyxos, concha, 
VOL. IX.—62 
