Shell small, probably not exceeding 8 mm. in length, compressed, very variable in height, which may be from 45% to 75% of the length. Color oyster-white under a very thin yellowish periostracum, which is partially flaked off. Base a narrow elongated oval. Anterior slope long and rather strongly convex, posterior slope short, concave around the apical whorls, then straight to the margin. Apical whorls prominent, from one and three quarters to two and one half, increasing rapidly in diameter after the first whorl, smooth, the tip glossy and standing out with considerable distinctness. They lie on the right side of the shell, turned backwards and downwards, their position varying from one rather high on the posterior slope to one somewhat lower down. Anal fasciole with numerous closely-set incremental lamellae. Fissure narrow and elongated, rounded at the upper end and narrowing in front to a point. It lies high on the front slope, its upper end rising to the summit of the shell, but still remote from the apex. From the fissure a fine groove runs down the front slope bordered on each side by a small ridge. Sculpture consists of very numerous radiating granulose ribs. The granules are very fine at first, increasing progressively in size toward the margin where they are rather prominent. There is no true concentric sculpture. Margin finely denticulated. Interior of shell glossy. The internal septum extends down for about three quarters the length of the fissure. The groove that runs from the fissure to the margin is more conspicuous on the inside of the shell where it is edged by very thin calluses which are prolonged to include the fissure.

I am unable to separate P. watsoni Dall from P. granulata Segucnza. A reexamination of Dall's types definitely places watsoni in Cranopsis and not in Puncturella s.s. as originally stated by Dall. P. watsoni agrees in all its characters with P. granulata; in having the fissure somewhat distant from the apex; in having a moderately long anal fasciole; and in possessing a well marked groove from the lower end of the fissure to the margin of the shell. Dall states that watsoni is higher than granulata but our studies indicate a wide range in the ratio of height to length, from 48% to 75%.' The ratio of height to length obtained from Seguenza's measurements is 66%, a figure well within the range of the ratios for the Western Atlantic form. Again, the anterior and posterior slopes vary in different specimens, a factor of course responsible for the variation of the height-length ratios given above. This variation may be directly due to immediate factors in the environment, that is, the objects upon which these animals are attached. This condition is probably not different from that exhibited by various species in the genus Crepidula, in which the slope of the shell varies tremendously, depending upon the flatness or curvature of the place of attachment. See Remarks under P. (Cranopsis) billsae.

The whereabouts of the type specimen of Puncturella (Cranopsis) granulata Seguenza is unknown to me. The type locality is the Miocene of Rometta, Messina, Sicily.
The lectotype of Puncturella watsoni Dall, here selected, is in the United States National Museum, no. 85140, from oft' Barbados, in 100 fathoms. It was collected by the Blake. Paratypes, in the same institution, from off Campeche Bank, and off Yucatan, Mexico; and in the Museum of Comparative Zoology, from off Bahia Honda, Cuba, and from off' Barbados.
EASTERN ATLANTIC: Azores. WESTERN ATLANTIC: Florida Keys and south along the coast of Mexico and through the West Indies.