188 TRICHODINA. 



e. Suture deep; striae very regular, projecting; size small, 



Species of East African Islands. 



Though so widely separated geographically from the pre- 

 ceding group, there is absolutely no conchological character 

 by which the following forms can be separated from the West 

 African more than specifically. 



7. T. COMORENSIS (Pfeiffer.). 



Shell ovate-turrite, solid, lightly and irregularly striatu- 

 late, white under a deciduous tawny cuticle. Spire elongate, 

 the apex rather obtuse. Whorls 7, the upper nearly flat, the- 

 penult, more convex, last whorl slightly exceeding one-third 

 the total length, somewhat tapering at base. Aperture sub- 

 vertical, elliptical, somewhat chanelled at the base ; columella 

 protracted to the base of the aperture, obliquely subtruncate^ 

 peristome obtuse, the margins joined by a rather thick callous. 

 Length 34, diam. 13, length of aperture 12, width 6 mm. 



Comoro Islands (Cuming coll.). 



Achatina comorensis PFR., P. Z. S. 1855, p. 211; Monogr. 

 iv, p. 605. 



Evidently related to T. monacha, but larger with one 

 whorl less. 



8. T. MONACHA (Morelet). PL 57, fig. 24. 



Shell oblong turrited, rather solid, marked with obsolete,, 

 irregular striae higher at the sutures; opaque, rather glossy, 

 chestnut-reddish, generally darker at the base. Spire tur- 

 rited, the apex rather obtuse. Whorls 8, a little convex, the 

 last % the total length. Columella slightly arcuate, obli- 

 quely truncate. Aperture oblong-oval, ashen within, the 

 margins obtuse, unexpanded. Length 32, diam. 12, alt, aper- 

 ture 12, width 6 mm. (Morel.). 



Great Comoro I. (Humblot). 



Acliatina (Homorus) monacha MOREL., Journ. de Conchyl. 

 1885, p. 290, pi. 14, f . l.Homorus m., KOBELT, C. Cab. p. 96. 



Larger and more solid than T. cornea, stouter and more 



