130 GASTROCOPTA, MASCARENE ISLANDS, ETC. 



Length 2.5, diam. above aperture 1.06 mm. ; aperture 0.8 

 mrn. long (figs. 1, .4). 



Length 2.2, diam. above aperture 1.03 rnm. ; aperture 0.75 

 mm. long (figs. 2, 3). 



The structure is that of G. scrvilis except for the absence of 

 a basal plica or its reduction to a minute rudiment, as in G. 

 s. riisei. The latter has slightly smaller columellar and pari- 

 etal lamellae. Compare also G. lyonsiana Ancey, which is 

 scarcely separable from seignaciana. 



In one specimen in the lot from Nossi-be there is a distinct 

 though low rounded crest behind the lip, of the same color as 

 the shell, and flattened out near the suture. Aperture as de- 

 scribed above, except that the basal plica is well developed. 

 Without more material I am unable to decide whether this is 

 a different race, or, as seems more likely, an extreme varia- 

 tion of seignaciana. It is this specimen which causes one to 

 doubt the specific distinction of G. microscopica. 



75. GASTROCOPTA TRIPUNCTUM (Morelet). PL 23, figs. 5, 7, 12. 



Shell minute, oblong, thin, entirely smooth, glossy, diapha- 

 nous, corneous; apex rather obtuse. Whorls 6, convex, the 

 last compressed basally, having two or three grooves behind 

 the lip. Aperture ovate-rotund, contracted by a strong pari- 

 etal lamina, another on the columella, and three punctiform 

 in the basal and outer margins. Peristome reddish, narrowly 

 expanded throughout. Length 3, diam. l^ Dam. (Morelet). 



Comoro Is.: Mayotte (E. Marie). 



Pupa tripunctum MORELET, Journal de Conchy!., xxx, 1882, 

 p. 189, pi. 10, f. 4. 



This small Pupa may be compared, at least as to shape and 

 size, with P. lienardiana Crosse, of Mauritius. But besides 

 that it is smaller and formed of less convex whorls, the teeth 

 are not of the same form in the two species, and are not 

 arranged in the same manner. The three punctiform teeth 

 placed at equal distances on the peristorne of P. tripunctum, 

 are replaced in P. lienardiana by a single basal denticle and 

 by two others immersed in the throat of the shell. It is, more- 

 over, not to be confused with P. exigua Ad., which has only 



