18 SUPPLEMENT TO GREAT OOLITE MOLLUSCA. 
Geological Position and Locality. The Great Oolite of Stonesfield, collected by Mr. 
Whiteaves. 
Rissoina Witcueiul, Lyc. Tab. XLIV, fig. 12. 
Testa elongato-turrita, anfractibus 6, latis, conveais, aut medio angulatis, longitudinaliter 
costellatis, costellis cirea 26—28, rectis, simplicibus, crebris; apertura ovato-obliqua, labro 
extus tncrassato. 
Shell elongately turreted ; volutions 6, wide, convex, angulated at their middle part, 
and encircled with a slender band at the mesial angle; the longitudinal little ribs are very 
closely arranged; they are smooth, narrow, perpendicular, and are united to the mesial 
band; from 26 to 28 in a volution ; the last volution is conformable with the others, both 
in figure and ornamentation; the aperture is of moderate size, it is oblique, ovate, but 
rather pointed at the two extremities ; the columella is curved in its middle; the outer lip 
is thickened. 
The angulated figure approximates to Rissoina duplicata, Sow., sp., ‘Gr. Ool. Mon.,’ 
i, p. 52); but the last volution is somewhat less expanded, the cost upon the spire are 
less conspicuous, and nearly three times as numerous. Mr. Witchell, who discovered the 
species, has kindly communicated several specimens which agree with each other in all 
essential particulars. 
Geological Position and Locality. he Great Oolite of Minchinhampton Common, 
associated with other minute testacea. 
RissoinA Minueri, Lyc. Tab. XLIV, fig. 10. 
Testa turrita subcylindrica, anfractibus (6) subconvewis, angustis, longitudinaliter costel- 
latis; costellis \7—18, rectis simplicibus; apertura ovato-semilunari, ad basim effusa ; 
labro extus valde incrassato. 
Shel! turreted, subcylindrical ; volutions (6) convex in their middle part, narrow, but 
with the sutures only slightly impressed ; longitudinally costellated ; costellae 17—18, per- 
pendicular, not very prominent, and plain; aperture ovately semilunar, oblique, expanded 
at the base, the outer lip having a considerable thickening. 
Allied to Rissoina acuta, Sow., but having the volutions more narrow and less con- 
vex, the sutures being less deeply impressed; the little ribs are much more numerous; 
the aperture is also larger and more effuse at the base. 
Geological Position and Locality. One of a series of mmute univalves obtained by 
Mr. Whiteaves in the Great Oolite of Minchinhampton Common. ‘The name is an 
acknowledgment of the discrimination of the author of ‘The Natural History of the Crin- 
noidea,’ who appears to have been the first person to discover the fossil riches of this locality, 
