Descriptions. — Scutellina scobinata. "T. parva. cinnamomea, rotundato-ovata, admodum elevata fornicata, apice terminali, deflecto; extus undulis concentricis et striis confertissimis radiantibus ornata et granulis elongatis obliquis inordinatis scobinata; intus subnacrea."
Ph. guttata: "...papierdunne Schale mit den wellenartigen Falten, dem Fehlen jeder Radialskulptur und dem deutlichen Septum der Innenseite; sie variert... in der Schuppenbildung die zuweilen fehlt..." (Thiele, 1909)

Discussion. — The name Ph. guttata, as far as I am aware, has never been used after 1909, except in the BMNH where on a label of a scobinata from the locotype, Ousimo, is written: "Ph. scobinata (Gld) = guttata Thiele". I know few specimens I can identify as scobinata. The type scobinata from Ousima, with four folded steps, is kept in the USNM. The two other specimens named scobinata in the USNM (N° 604284 from Zanzibar and N° 243005 from Manhacas Isl., Philippines) are different and seem to me P. galathea. In the collection of Dautzenberg there is one from Nou Isl. (6.5 x 4.3 x 1.5 mm) named rouxi Brazier. I have not found this name in the literature, but Brazier (1880: 389) mentions several habitats for Scutellina cinnamomea, for instance: NSW (Gld), Noumea, New Cal. (R.C. Rossiter), Nou Isl., near Noumea (M. Roux). We see that Mr. Roux collected at Nou Island. It is possible that Dautzenberg received a specimen from Mr. Brazier or Mr. Roux, shell which had, or received later, the name rouxi (ms.?) while different from cinnamomea. Trappe G. received several specimens from Rangiroa Isl., Tuamotu. I examined the radula of one of them and figure a specimen in my collection which has 235 denticles on the margin, 22 concentric folds and more than 130 concentric ridges, ornamented with imbrications.
I now consider guttata as synonym of scobinata, a species having a few concentric steps of wavelike folds, no radial sculpture and covered with drops or prickles. I am not sure that the smooth specimen drawn by Thiele, pl. 6, fig. 14, is the same. In case it constitutes another species, it is preferable to keep the name guttata (in latin: grained) as synonym of scobinata (in latin: scraped, grated, rasped), to rename the smooth one and to select a lectotype for it in Berlin.

(Synonym: Scutellina cancellata Pease, 1861b.) Length, 9.5 mm; diameter, 7 mm. Shell: patelliform, fragile; apex extending to the posterior margin; white to red-brown. Sculpture: fine axial ribs cancellated by spiral threads of equal or lesser diameter, the axials and spirals forming nodules at the intersections of the ribs; interspaces smooth; margin fimbriated by the external sculpture. Color: white or red-brown; interior porcelaneous. Animal: foot and proboscis red.
These gastropods are occasionally found under rocks in tide pools; the animals move rapidly over the substrate when disturbed. The veliger larvae are found in the plankton throughout the year (J. B. Taylor, 1975).
P. scobinata was described from Okinawa; it also occurs in Madagascar, New Caledonia, and the Cook and Marshall Islands.