102 
Gemis — MITCIIELLIA, L. G. de Koninck} 
Shell elongate cylindrico-conical, composed of a rather large number 
of spiral whorls; aperture long and strongly constricted, external margin 
non-sinuated, doubly arched vertically, thickened and reflected outwards; 
surface striated in a direction contrary to the axis of the shell. 
Ohservation . — After having tried in vain to place in some already 
known group the unique specimen that has the characters I have just 
detailed, I find myself cornpelled to propose a new genus for the creation of 
which it has served as the type. I have dedicated this genus to that intrepid 
traveller. Colonel Mitchell, who was the first to bring to notice a number 
of Australian Palaeozoic fossils. Put with the establishing of this genus all 
the difliculties of classification have not ended, and it remains to work out its 
affinities with the groups already known. In examining the principal families 
of the Gasteropoda in which the aperture is elongate and narrow, of which 
the outer edge of this aperture is not broken, but often folded outwards and 
thickened, and in which as well the surface is generally ornamented with 
striae or furrows parallel to the sutures, it will be concluded, without diffi- 
culty, that it is the family Buceinidoe which comprises the greatest number of 
species showing these different characters. It is, then, in this family, and 
near the genus Columbella, that I propose to class the genus IlitchelUa. In 
the description of the only specimen at present known I will be obliged to 
repeat a great number of the characters I have mentioned above. 
Mitchellia steiatula, L. G. de Koninck. 
PI. IV, Fig. 12. 
Shell of moderate size, composed of several spiral whorls, little convex, 
suture linear, surface ornamented with a large number of fine striae, well- 
marked though not deep, and parallel to one another and to the direction of 
the sutural margin. The body whorl ends in rather narrow aperture, of 
Avhich the anterior canal and lip are prolonged beyond the base of the 
shell. The outer margin of the aperture is curved and folded inwards oppo- 
site the middle point of the inner margin, which is only faintly bent in the 
opposite direction, so that the two lips are close together and almost parallel 
to one another. The outer lip is rather strongly folded outwards, but is 
smooth and without teeth ; the inner lip is thin and without any projection. 
^ [Fischer classed MitclieUia in the Subulitida;, and was also of opinion that it is closely to Laube’s 
E uchrytalis. Manuel de Conchyliologie, 1887, p. 771. — W.S.D.] 
