Shell resembling the preceding in its general features, but larger and stouter, and differing in details of sculpture, etc. It is best described by comparing it with Theta chariessa. The nucleus is similar and there are seven subsequent whorls; the keel is less prominent, there is a narrow shallow groove behind it, and then two sharp threads marginating the fasciole, which are more distinct on the earlier whorls; the spiral threads on the fasciole are crossed, as in T. chariessa, by fine arched ripples, but in P. hadria these ripples are more numerous, finer and closer together, they follow the incremental lines, and, as the sinus is less profound in P. hadria, they are less deeply concave; one of the most marked differences is a series of small oblique riblets, which begin in front of the fasciole or on the keel itself, especially on the earlier whorls, cutting its continuity, and continued obliquely in front of it nearly or quite to the suture as threads reticulating the spirals; this feature becomes obsolete on the last whorl or half-whorl, and is stronger in archibenthal specimens from the Gulf of Mexico than in those from off the Carolina coast; on the base of P. hadria the threads are hardly divisible into two series, and the alternations of size are very slight, and occur in every other thread if at all, instead of several fine ones intercalated between two primaries ; the aperture, roundness of the base, outer lip, etc., are much as in T. chariessa, but the notch is not so deep, the pillar is not quite so straight, and the canal is a little twisted and plainly somewhat recurved. Max. lon. of shell (of same number of whorls as the specimen previously described under P. catasarca), 27.0 mm; of last whorl, 19.0 mm; max. lat. of shell, 13.0 mm.

The Gulf specimens, as usual, show a thinner and more glistening epidermis over a sharper and more delicate sculpture and a thinner shell. Gymnobela engonia Verrill may belong in this vicinity, but it has much more the aspect of a genuine Bela.

Between the delta of the Mississippi and Cedar Keys, Florida, to North Carolina, off Cape Fear.