448 GASTEROPODA OF THE INFERIOR OOLITE. 
Description : 
Height : 5 : 5 - 26mm. 
Basal diameter : ; 4 : 32° mm. 
Spiral angle F . 85°. 
This is a less broadly tabulate form than Te one previously described, the 
whorls being higher and the apex sharper. In some cases also the whorls are 
more numerous (six to seven). In other respects similar to 7. gradus. 
Relations and Distribution.—The figured specimen is from Stoford, and may 
be taken as the representative of 7. affinis. Lycett figured his 7. carinata with 
the fossils of the Spinosa-stage. 
As before observed, we are almost entitled to look upon 7’. caliz, T. affinis, and 
T. gradus as varieties of one species; where 1’. gradus is a large tabulate form 
with about six whorls and an obtuse apex, 7. affinis is a large subtabulate form 
with higher whorls and a sharper apex; whilst 7. caliv is a small subtabulate form 
with five whorls and a very obtuse apex. 
389. TrocHotoma pEPReEssIuscULA, Lycett, 1850. Plate XLI, fig. 10. 
1850. TrocnwoTtoma DEPRESSIUSCULA, Lycett. Ann. Mag. Nat. Hist., 2nd ser., 
vol. vi, p. 417. 
1853. _— —— — Proe. Cotteswold Nat. Club, 
vol. i, p. 78. 
Cf. also — DIScoIDEA, Rdmer. Morris and Lycett, Grt. Ool. Moll., 
pt. i, p. 84, pl. x, fig. 10. 
Bibliography, Sc.—T. depressiuscula was not accepted by Morris in 1854, nor 
by Hudleston and Wilson in 1892. The type specime™ is in the Jermyn Street 
Museum. 
Description : 
Height : : : ‘ «. ,l3)anm:. 
Basal diameter : F ; ; 24. mm. 
Spiral angle : ‘ ~ LOO: 
‘** Depressed; whorls five, narrow aia angulated ; ribs below the angle three, 
above more numerous. Upper surface of the whorls concave, lower flattened ; base 
striated, excavation large not deep, height half the basal diameter.” 
Relations and Distribution—More depressed even than 1’. gradus, and less 
strongly bicarinated. It is nearly related to ‘ 7’. discoidea, Romer,” of the Great 
Oolite Mollusca, and may be the same as that form. 
