Gen. Conchyliolithus. Fam, NAUTiLiXi®. 15 
ttt- univalvium. 
* s.* Nautillta:. 
* a. a. * Involuti. 
26. Conch. Nautilites involutus umbilicatus globosus, ambitu integro, aper- 
tura coarctata, dissepimentis dentato-sinuatis. 
Tab. 7. Fig. 3, 4, 5. 
Varictas. 
b. V. lateribus planiusculis. 
Spherical Nautiliie. 
Sccles : strata vctusta, calcaria. 
Castleton, &cc. 
SPECIMINA. 
a. S. umbilico obsolete s. farcto. 
b. S. suturis dissepimentorum obsoletis. , 
Obs. V. b. appears to exhibit a real variation in the structure of the original, and not an acci- 
dental form, arising, as at first sight might be supposed, from compression during the petrifying 
process. 
S. b. with indistinct sutures most common — We have remarked, that the sutures are generally 
more evident in specimens consisting of black or dark-coloured marble, than in those found in the 
whiter kinds of limestone. 
27. Conch. Nautilires? involutus imperforatus subglobosus striatus : striis 
transverso-obliquis ; linea dorsali conjungente, apertura ampliata, disse- 
pimentis ? 
Tab. 40. Fig. 1, 2. 
Far iet ales. 
a. V. linea dorsali plana lata, striis acutis distinctls. Fig. 2. 
b. V. linea dorsali parum convexa lata, striis subobsoletis confertis. Fig. 1. 
c. V. linea dorsali tenuissima, cicatriculae instar, striis confertis. 
Wide-mouthed Nautilite. 
Sedes : strata vetusta, calcaria. 
spharicus. 
hiidcus. 
