68 MOLLUSCA FROM THE GREAT OOLITE. 



Shell small, conical; spire acuminated; whorls rather flattened, and encircled with 

 four imbricated striae ; the last whorl is somewhat angulated towards its base. 



The imbricated striae are fine and closely arranged, those beneath the angle upon the 

 last whorl are larger; the aperture is semilunar and contracted. As compared with 

 M '. decussata, this shell is more lengthened, the apex pointed, and the encircling striae 

 much fewer. 



Locality. It is rare, and occurs, with the species before mentioned, at Minchinhampton. 



MONODONTA FORMOSA. Plate XI, figs. 6, 6 a, b. 



M. Testa turbinatd, spird subdepressd, prominuld, oltusd; anfractu ultimo in media 

 carinato, striis transversis crebris tenuissimis cincto; carind lesviyatd, rotundatd, obtusd, 

 striis supra carinam positis mat/is elatis; upcrturd semilunar i subcontractd. 



Shell turbinated, spire rather depressed, small, obtuse ; the last whorl carinated in its 

 middle part ; the carina smooth, rounded, and obtuse ; the last whorl has likewise trans- 

 verse, closely arranged, fine, and crenulated striae, those above the mesial carina being 

 larger than the others ; aperture semilunar, somewhat contracted. 



In the greater number of specimens, more especially those of large dimensions, the 

 encircling striae are obsolete, the only markings being the lines of growth. Diameter of 

 largest specimens, 4| lines. 



Locality. It is abundant and common to all the shelly beds near Minchinhampton. 



MONODONTA DECUSSATA. Plate XI, figs. 9, 9a. 



M. Testa parvd, conicd; apice obtuso; anfractibus planis, suturis impressis; striis 

 crebris transversis et longitudinalibus decussatis. 



Shell small, conical ; apex obtuse ; whorls flattened, their sutures impressed, encircled 

 with numerous transverse striae, decussated and impressed by others longitudinally. 



This shell is more obtuse than M. imbricata ; the last whorl is more cylindrical than 

 the others ; the lines upon its surface are so delicate as to be scarcely visible, unless under 

 a magnifier. 



Locality. It is rare, and occurs with M. imbricata, in the soft shelly Oolite of 

 Minchinhampton Common. 



MONODONTA LABADYEI, Archiac, sp. Plate XI, fig. 2; var. fig. 11, 11. 



TROCHDS LABADYEI, Archiac. 1843. Mem. Soc. G6ol. de France, iii, p. 379, t. 29, 

 figs. 2, la. 



TURBO D'Orb. 1850. Prod. Paleont., p. 301. 



? MONODONTA J^EVIGATA, Goldfuss. Petref., p. 101, t. 195, fig. 5. 

 ? TURBO DESLONOCHAMPSI, Desk. Elem. de Conchyl., t. 68, figs. 17, 18. 



