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. 4.1, length of aperture 5.1 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 ISTHNICUS, 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 44 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. 10.5, alt. 3.7 mm. 
Panama City, in Chinese wells. Col- 
lected by James Zetek, Sept., 1918. 
Planorbis liebmanni Phil., maya and 
orbiculus Morel., are flatter shells, with 
the spire wider. P. boucardianus Prest. has a more oblique 
