TRICHODINA. 183 



striated ; columella thinly truncated ; aperture small. White, 

 covered with a chestnut-horny epidermis (Reeve). 



Habitat unknown (Mus. Taylor). 



Acliatina marmorea REEVE, Conch. Icon, v, pi. 23, f. 125 

 (March, 1850). PFR., Monogr. iii, p. 499. 



Morelet considered Reeve's type of marmorea to be a worn 

 specimen of his own A. barbigera; a conclusion which seems 

 to me well founded. The description of the latter follows: 



A. barbigera Morelet (PL 55, figs. 94, 95). Shell club- 

 shaped turrited, solid, opaque, white, longitudinally plicate- 

 costulate, covered with a dark chestnut, membranously fila- 

 mentose cuticle with spiral ridges bearing scale-like fringes. 

 Spire long, acute, the suture impressed. Whorls 9, plano- 

 convex, the last obsoletely angulate at the base, one-fourth 

 the length of the shell. Golumella arcuate, pale, tapering 

 truncate. Aperture small, semioval, blue within; peristome 

 simple, unexpanded. Length 43, diam. 12 mm. (Morel.). 



Island of S. Thome: Forests of Mt. Cafe etc., at 400 to 

 1450 meters elevation. 



Acliatina barbigera MOREL., Journ. de Conch, xiv, 1866, p. 

 160 ; Yoy. Welwitsch p. 75, pi. 9, f . 5. CROSSE, J. de C. 1868, 

 p. 134. PFR., Monogr. vi, p. 234. Homorus barbiger CROSSE, 

 J. de C. 1888, p. 21. GIRARD, Jornal de Sci. Math. Phys. e 

 Nat., Lisboa, (2), iii, p. 41 (1893). KOBELT, Conch. Cab. p. 

 98, pi. 26, f. 7, 8. 



This species is very variable in the length of the spire and 

 the . convexity of the whorls, according to Mr. Girard. At 

 Portinho Mr. Newton found two fresh sinistral specimens; 

 and among 26 worn examples found on the beach at Bua Bua, 

 washed down from the high land, there were 10 sinistral ones. 

 The largest specimen of barbiger collected by Mr. Newton 

 measured 50 mm. long, 15 wide. 



The shell, Morelet writes, is quite thick, corneous, whitish, 

 grooved with oblique, flexuous pliciform riblets not very regu- 

 lar in appearance, and less apparent when the shell is covered 

 with its epidermis. This epidermis is of a deep chestnut 

 color and fibrous texture. It is finely striated longitudinally, 

 but what makes it remarkable are the regularly spaced, fine 



