90 



MONODONTA. 



middle of the columellar area tvitli a longitudinal semilunar groove, 

 frequently irregularly curved ; basal notch or canal oblique, squar- 

 ish, wider than deep, not denticulate in the middle. 



Alt. 23, diam. 2(3 mill. ; alt. 17, diam. 17 mill. 



Natal ; Ins. Socotra ; Mascat. 



T. vermiculatus Fischer, Journ. de Conch., 1874, p. 373, et Coq. 

 Viv., p. 228, t. 74, f. 3. — T. australis (in part) Philippi, Conchy I. 

 Cab., t. 27, f. 6, 7. 



This specie.s of which numerous specimens collected by Dr. 

 KuscHENBERGER at Mascat, Aralna, are before me, is allied to M. 

 australis and M. dama. From the former it is distinguished by the 

 more depressed form, less numerous whorls, smooth surface almost 

 without spiral ridges, the coloration, the more numerous finer grooves 

 within the lip, and the smaller tooth of the columella. The color- 

 ation is different from that of INI. dama, which is, however, a very 

 closely allied species. 



There is great variation in color in this species. In some spec- 

 imens red predominates ; in others green ; and often the general 

 effect is an olive shade. There is usually a subsutural series of light 

 and dark dashes. The numerous narroAV red spiral lines are char- 

 acteristic, but are also found sometimes on M. canalifera, — a species 

 separated constantly from this by its deep basal notch, denticulate 

 in the middle. 



It is rather difficult to distinguish the species of this grou}) ; but 

 attention to the differential characters pointed out under each, will 

 enable one to see that although closely allied they are distinct. 



Section Austrochlea Fischer. 



Austrochlea Fischer, Manuel de Conchyl., 1885, p. 820. 

 M. coNSTRiCTA Lamarck. PL 20, figs. 6, 7. 



Shell imperforate, thick, solid, lusterless ashen or whitish, obscurely 

 marked with black zigzag lines and stripes, or with spiral articulated 

 zones or with spiral stripes of black ; sometimes nearly unicolored ; 

 spire conical, apex acute; whorls about 5, convex, the first eroded, 

 the penultimate very strongly spirally tricostate, the last with about 

 seven strong carime ; aperture oblique ; outer and basal lips either 

 thick and multi-lirate within, or rather thin and slightly furrowed 

 at the j)laces of the principal carinie ; columella short, oblique, sub- 

 dentate at base, at the insertion spreading in a strong callous upon 

 the parietal wall. Alt. 28-83, diam. 22-28 mill. 



