. The Conchologists' exchange. Mollusks. 78 THE NAUTILUS. ternal folds or callus. There is a strong, deeply entering diag- onal parietal lamella, a smaller one below it; columella termin- ating in a spirally entering lamella. Length 8, diam. , length of aperture mm. (fig. d, apex lost). Panama City and Paitilla, near the city, collected by James Zetek, 1917. Also Taboga Island. This species stands near P. triplicata (Anton) and P. acuta (Orb.) both of which have similar teeth. It is, however, de- cidedly narrower than the first, wider than the second, so that while I hesitate to add ano
. The Conchologists' exchange. Mollusks. 78 THE NAUTILUS. ternal folds or callus. There is a strong, deeply entering diag- onal parietal lamella, a smaller one below it; columella termin- ating in a spirally entering lamella. Length 8, diam. , length of aperture mm. (fig. d, apex lost). Panama City and Paitilla, near the city, collected by James Zetek, 1917. Also Taboga Island. This species stands near P. triplicata (Anton) and P. acuta (Orb.) both of which have similar teeth. It is, however, de- cidedly narrower than the first, wider than the second, so that while I hesitate to add another species to this genus, it appears that none of those described will receive It. Phytia rhoadsi (Pils.), described as a Marinula, and P. setifer (Caop.) are more northern species, the former somewhat related to P. brevispira. In this species the aperture is longer than the spire, as in Mari- nula, but the other characters are decidedly those of Phytia (Alexia). Planorbis isthmicus, n. sp. The shell is compressed, the thickness about one-third of the diameter, thin, very pale brown, somewhat transparent, glossy. Concavity of the right side showing three whorls and a central pit, that of left side shallow, showing 4J whorls, the last whorl more convex near the sutures, rounded peripherally, not deflected to- wards the left near the aperture. Sculp- ture of fine growth-lines, very distinctly decussated by fine spiral lines on the inner whorls, the spirals weak, in part obsolete, on the last whorl. The aperture is ob- lique, heart-shaped, the lip thin. Diam. , alt. mm. Panama City, in Chinese wells. Col- lected by James Zetek, Sept., 1918. Planorbis liebmanni Phil., may a and orbiculus Morel., are flatter shells, with the spire wider. P. boucardianus Prest. has a more oblique. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly rese
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectmollusks, bookyear188
