TJROCYCLUS. 163 



sunken lines. Margin of the foot with a series of small black 

 specks. Near the mouth of Zambesi River, Central Africa. 



U. FLAVESCENS, Keferstein. PL 35, figs. 34-36. 



Grayish brown to dark orange, keel and lateral ridges lemon, 

 sulci dusky. Shell very pale yellowish. 



Length, 1 inch contracted, or 3 inches when in motion. 



Mozambique. 



Var. PALLIDA, Gibbons. Shield and body opaque white, with a 

 faint yellowish tinge. 



The variety and type are found on bushes. Ordinarily the 

 shell is invisible, the longitudinal slit in the shield being closed, 

 but the animal has the power of dilating it so as to show the shell. 



U. COMORENSIS, Fischer. PI. 36, figs. 47, 48. 



Animal, discolored by alcohol, apparently without color 

 marking. Shell extremely fragile, composed of a thin calca- 

 reous plate with an epidermis which extends beyond its margin 

 anteriorly and laterally. Length, 60 mill. 



Ins. Mayotte, Comoro Is. 

 U. VITTATUS, Fischer. PL 36, fig. 49. 



Animal, discolored by alcohol but showing a dark stripe on 

 either side of the granular mantle, the centre marbled. Smaller 

 and narrower than the preceding species and less carinated 

 behind, the mucous pore is smaller, the dorsal slit less posterior, 

 the mantle granular. Shell not described. Length, 42 mill. 



Ins. Mayotte, Comoro Is. 

 U. LONGICAUDA, Fischer. PL 36, figs. 50, 51. 



Yellowish, unicolored or maculated with black; shield very 

 small, granulated, with the posterior slit very small; tail narrow, 

 with small pore. Length, 50 mill. 



Shell small, oval, thin, concentrically striated, nucleus in the 

 posterior centre, somewhat'prominent. 



Ins. Nossi-Comba near Madagascar. 

 U. BUCHHOLZI, Martens. PL 36, fig. 52. 



Greenish, marbled with a darker tint, especially on the shield, 

 margin of the foot whitish. Length, 72 mill. 



Aburi, Gold Coast, W. Africa. 



The figure was made from a colored drawing ; no description 

 published. 



