A rather large Carychium species (shell 1.8 to 2.1 mm high), with a slender, rounded conical shell, which exhibits
(1) prominent, sharp, transverse riblets,
(2) a distinctive, granular microsculpture on both the proto- and the teleoconch, and
(3) a sinuous edge of the comparatively long internal part of the parietal lamella.

Description. — Shell rounded conical in outline, whitish or more glassy translucent (when very fresh), with 4,5 to 5,5 rather inflated whorls. Teleoconch with prominent, regular, transverse riblets, which are usually not very closely spaced. Both proto- and teleoconch provided with a conspicuous, granular microsculpture. Aperture oval, in front view oblique, with a broadly reflected and strongly thickened apertural lip; outer lip with a prominent denticle, inner lip showing the relatively high outer end of the parietal lamella and the less conspicuous outer end of the columellar lamella. The height of the aperture is 0.36 to 0.40 of that of the entire shell. The shells are 1.8 to 2.1 mm high and 0.85 to 1.1 mm broad; they are 2.0 to 2.2 times as high as broad.
The frontal part of the body-whorl should be partly removed in order to study the important internal part of both the parietal and the columellar lamella. Both lamellae have a thickened, rounded edge. The edge of the parietal lamella is distinctly sinuous, with a conspicuous, adapical curve in the second quarter of the body-whorl (counted from the penultimate whorl on). The columellar lamella is much lower than the parietal one and its edge is not clearly sinuous; only the latter lamella is still very pro¬minent where it enters the penultimate whorl from the body-whorl.

C. ibazoricum differs from the European species C. minimum Müller, 1774, C. paganettii Zimmermann, 1925, C. tridentatum (Risso, 1826), and C. mariae Paulucci, 1878, most clearly by its granular microsculpture and the very prominent transverse riblets. The first two species also differ from C. ibazoricum by their simple parietal lamella, which does not have a sinuous edge .
C. ibazoricum is similar in shell sculpture to the American (sub)species C. exile canadense Clapp, 1906, and C. clappi Hubricht, 1959 (see Burch & Shrader van Devender, 1980: figs. 108, 110), which differ, however, by having more cylindrical and narrower shells; as far as can be concluded from the cited figures, there is no prominent, granular microsculpture in the American taxa. In C. ibazoricum the palatal denticle is much more prominent than it is in each of the Carychium species from North America discussed by Pilsbry (1948: 1051-1062) and Burch & Shrader van Devender (1980). On the Iberian peninsula the species is more variable in shape and dimensions than it is on the Azores.

C. ibazoricum is known from the Iberian peninsula (Portugal) and from the following Azorean islands: Sao Miguel, Terceira, Sao Jorge, Faial, and Pico.