34 
AMERICAN JOURNAL 
S. testa ovato-conica, tenuicula, vertice sub-oblique acuminato 
et intorto ; sordide virescente, lineis fuscis irregulariter radiatim 
filosa, intus nitente castanea. 
Hah. Tristan d’Acunba, Rve. (in error.) Grange Harbor, 
Tierra del Fuego. U. S. Exploring Expediiion. 
External Appearance. The epidermis on thè head and sides 
of thè foot is granulose, rough to thè touch. The mantle edge 
is simple, slightly tuberculose and continuous over thè head and 
lobe. The colors, as far as could be judged from thè alcoholic 
specimens, had been purplish. The edge of thè mantle was dis- 
tinctly marked by well defined stripes of dark brown or blackish, 
and white ; corresponding to thè riblets and dark intervals of thè 
shell. The head or muzzle is rounded, with thè corners some- 
what produced or triangular. The sides of thè foot are broad, 
and thè sole is smaller in proportion to thè aperture of thè shell 
than in most patelliform shells. The lobe beneath thè pulmon- 
ary opening is triangular and large. It is pierced for thè anus. 
On thè neck behind thè head is a small papilla, indicating thè 
foramen of thè genitalia. It is on thè right side. The end of 
thè muzzle is flattened, and thè mouth is not conspicuous. 
Alimentary System. The buccal mass is proportionately 
small, and not as muscular as in most pulmonates. The oesopha- 
gus leaves it from thè middle of thè superior surface, and at thè 
posterior end of thè buccal body is constricted and bound down 
by a collar of nerves and muscular fibres. A small elongated 
salivary gland lies on thè upper surface of thè buccal mass, on 
each side of thè cesophagus, and empties into it by thè posterior 
termination of thè gland. Behind thè collar thè alimentary 
canal is broadly dilated, forming a sort of crop. This is slightly 
constricted, and behind thè constriction is thè true stornach. 
This is rhoraboidal in shape. The intestine leaves thè stornach 
at its anterior end, on thè left side, and is reflected over thè 
lattei’ in a broad loop to thè right, when it turns again, and 
passing around thè posterior end of thè body opens through thè 
lobe, which closes thè pulmonary orifice. Some small muscular 
fibres bind thè posterior end of thè stornach to thè foot. 
The jaw is horny and dark brown. The cutting edge is 
smooth and arcuateci. The portion which is inserted into thè 
flesh is striated and produced into long, stout, muscular fila- 
ments, which are not represented in thè figure. There are twm 
well marked notches on thè superior edge. The jaw is deeply 
grooved behind and thè inner surface striated. 
The radula is stout and of a dark brown color. 
The formula is 50T’50 or 20’30T‘30’20. 
