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.
This is a very interesting shell, being one of the links between the land and marine mollusca—the species of the genus being chiefly tropical, occurring at Cape St. Lucas, Panama, West Indies, Africa, and Isle of France, according to Binney, who says that they inhabit crevices of rocks, especially those exposed to the full force of the tide; but being pulmonate, they can probably live long with but little moisture. On the rocks the living shell would be mistaken for a Lacuna or Littorina, and the form of our species reminds one strongly of Succinea Oregonensis.
A communication was received from Dr. Canfield of Monterey, giving an account of the discovery in Monterey Bay, of a fish, pronounced by the naturalists of the Smithsonian Institution to be a new species of Bdellostoma, a genus not previously known to exist nearer than the coast of Chili.
Mr. Falkenau made some remarks on the use and value of the spectroscope in chemical analysis and in other scientific investigations.