On a New Species of Pedipes, inhabiting the Coast of California.
BY J. G. COOPER, M.D.
PEDIPES UNISULCATA, Cp. [Fig. 29].
Fig. 29.
Sp. ch. P. t. Lacunoida, oblique ovata, peripheria laterali subrhomboidea, translucente succineo-brunnescente, spira producta, apice obtusa, anfr. iv et dim.; tertio tumido, sulcis iv, posteriori solum valde impresso, in ultimo evanescente; ult. lineis incrementis irregularibus sulco undulatis; punctis impressis numerosis sparsim ornato; apertura ovata, labro acuto purpurescente intus callo duplicato medio subtuberculoso; labio columellari albo, calloso, in piano aperturæ expanso; margine interno subverticali dentibus duobus subacutis, superiori majore; callo tenui expanso in parietem interno, dente lamellari valido in plano parietis externi expanso, dimidium latitudinis aperturæ transeunte; intervallis dentium parietumque equalibus.
Specific Characters.—Shell like a Lacuna, obliquely ovate, the lateral outline subrhomboid, translucent, amber-brown, the spire produced, apex obtuse, whorls 4½, the third swollen, with four shallow grooves, the posterior one only much impressed, but vanishing on the last whorl; body with irregular lines of growth undulating across the groove; numerous scattered impressed points; aperture ovate, the outer lip acute, purplish, with a double callus within slightly tuberculate at the middle; columellar lip white, callous, expanded in the plane of the aperture; its inner margin subvertical, with two subacute teeth, the upper largest; a thin callus expanded over the inner wall, with a strong lamellar tooth expanded in the plane of the outer wall, and crossing half the width of the aperture; intervals between the teeth and walls equal.
Long. 0.32 unc. = 8 mill.
Lat. 0.22 ”
Long. spiræ 0.12 = 3 ”
Long. apert. 0.25 unc.
Lat. ” 0.19 unc.
Div. 40° and 45°.
Hab.—San Pedro, Cal., estuaries.
Only four specimens were found dead near the old landing, close to the mouth of the bay, in October, 1861. I supposed them to be P. brata Binn, but they are nearly three times as large, not lirate, etc. That species is catalogued by Carpenter as among the collections from San Diego, in the Supp. Rep. etc., 1863, pp. 612, 647, 673, but I do not find it in the State collection. Those described are fresh and shining in the mouth—dull, but not much worn, outside.