THE GENUS VERMICULUM OF MONTAGU. 565 
Plate XV, fig. S. a anc? each side of the body ; e, the 
mouth ; a lateral view of the tooth. 
This species appears to be the Serpula semimdum of 
LiNN^us, — the Serpida subovalis umbilico pervio of Wal- 
KEE, Test. Min. tab. 1. f. 1.,— and the Serpula ovalis of 
Adams, Linn. Trans, vol. v. p. 4. tab. 1. fig. 28. 29. 30. 
The shell is in general a little compressed, and the external 
margin subacute. Three chambers are usually visible on 
one side, and four on the other. These are slightly striated 
across, and have the limits of separation well defined. The 
tooth is a triangular thin plate, a little recurved at the tip, 
and so persistent as frequently to remain after the outer 
side of the chamber has been destroyed, 
2. F. oblongum. Test. Brit. 522. tab. 14. f. 9. Mouth 
round, with a pedunculated forked tooth. Plate XV. fig. 4. 
d, e, each side of the body ; Jl the mouth and tooth. 
Three chambers are usually visible on one side, and two 
on the other. In the first, the middle chamber is partially 
embraced by the outer ones, so that a shallow depression is 
formed at the outside of the line of junction. On the other 
side of the shell a similar depression is observable, and pro- 
duced by the margin of the last chamber rising on the side 
of the second. The chambers are rounded externally. 
3. V, subrotundum. Test. Brit. 521. Mouth depressed, 
toothless. Plate XV. fig. 5. g and each side of the body ; 
«, the mouth. 
This appears to be the Serpida subrotunda doi^so elevato 
of Walker's Test. Min. tab. 1. f 4. This shell differs 
from the two preceding species in being globular. The 
chambers are three, sometimes four in number, inflated and 
wrinkled. The fourth chamber, when present, seems al- 
ways imperfectly formed. 
