CHAPTER IV. 
PARTULA FRAGILIS Feérussac. 
The above-named species is rarely found except in portions of the northern 
half of Guam, and, even in the areas of its occurrence, its numbers are relatively few; 
hence its features of interest are quite different from those of P. gibba and P. 
radiolata, whose abundance, diversification, and wide distribution render them 
especially important. There are no figures of the shell of fragz/is in the literature, 
but the circumstances are such as to leave no doubt that the material collected 
during the present research must be assigned to the species described by Férussac 
in 1821 as P. fragilis... In 1894, von Moellendorf described the same species as 
P. quadrasi? from material collected by Quadras in Guam, but the earlier name and 
description must be accorded priority. Férussac’s original diagnosis is translated 
as follows: 
Shell ovate-elongate, perforate, fragile, striatulate, pellucid, reddish; spire obtuse, 
sutures strongly marked. Whorls 4, the last ventricose, subcarinate, larger than the 
rest. Aperture ovate, peristome subreflexed. Mariana Islands. 
The description given by von Moellendorf is longer and more satisfactory in 
its detail; it is as follows: 
Shell dextral, narrowly and half-covered perforate, rather ventricose ovate-conic, 
very thin, pellucid, delicately striatulate transversely, decussated by closely-crowded 
spiral lines; a little shining, pale buff variegated with narrow darker and whitish streaks, 
sometimes ornamented with two indistinct bands. Spire subregularly conic, the apex 
somewhat obtuse. Whorls 4, a little convex, separated by an appressed, marginated 
suture, the last whorl quite convex, nearly tumid. Aperture rather oblique, oval, a little 
excised; peristome simple, thin, well expanded, the columella dilated above, recurved, 
forming a distinct angle, almost channeled, with the parietal wall. Length 15, diameter 
10.5, aperture 9x 7mm. Mariana Islands (Quadras). 
Pilsbry comments as follows, on p. 318 of the Manual: 
An unfigured species that seems to differ from the small form of P. radiolata in sculp- 
ture, and by having fewer whorls. It is possibly identical with Férussac’s P. fragilis, a 
lost species which has not been figured. 
Pilsbry’s suggestion is correct, in my opinion. In the first place, the descrip- 
tions given by Férussac and von Moellendorf seem to refer to identical species of 
shells. Secondly, there can be no doubt that Quadras secured in Guam the speci- 
mens which von Moellendorf described and named in his honor. Thirdly, Gaudi- 
chaud-Beaupré is cited by Férussac as authority for the statement that fragilis 
was obtained at Guam; the same naturalist collected the first-known specimens of 
gibba during the visit to Guam of the de Freycinet expedition, likewise described by 
Férussac in 1821. The work of Gaudichaud-Beaupré bears ample evidence of his 
accurate powers of observation, and it is not likely that he would have made an 
error in the matter of the locality from which he obtained the shells of either species. 
Finally, the present writer’s collections in Guam comprise a sufficient number of 
1 Tableaux Syslematique des Animaux Mollusques, 1821, p. 66. 
2 Nachrichtsblatt der deutschen Malakologisches Gesellschaft, vol., XXVI, p. 15, 1894. 
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