1873.] F. Stoliczka — Land-shells of Penang Island. 15 



The animal of the Penang species, when fully extended, equals in length 

 about twice the longer diameter of the shell ; back roundly flattened above, foot 

 posteriorly obtusely ridged, terminating with a large gland which is superseded 

 by a small horn ; pedal row very distinct and the edge of foot below obliquely 

 striated. The general colour of the body is pale or livid grey, with a general 

 reddish tinge when full grown. A pale yellow (in young), or more or less 

 distinctly cinober red (in adults), stripe extends along the centre of the back 

 and the superior ridge of the foot, the former is bounded on each side by a 

 broad black stripe, originating at the base of each peduncle and continuing 

 to the mantle, and below this stripe there is again a yellowish or red line. 

 The posterior red band is only edged with black. The sides of the foot, 

 both anteriorly and posteriorly, are more or less distinctly variegated with 

 impure black and tinged with red ; front of head between the two pedicles and 

 tentacles with a black spot ; pedicles and tentacles generally greyish, the latter 

 with a reddish tinge, and with pale, rather large, globular tips, the former 

 with a black ring at the base where the longitudinal black bands begin. 



The mantle is moderately thickened. The right shell lobe is entirely 

 obsolete, or only indicated by a very slight extension of the edge, a short dis- 

 tance below the upper angle of the aperture of the shell. Sole of foot divided by 

 a longitudinal groove. The right neck lobe is large and extends as a moderate- 

 ly broad fringe to near the retractor muscle where it terminates with a free end. 

 The left neck lobe is smaller with a linguiform free outer end. The left outer 

 edge of the mantle is externally also entire, like the right one, but about the 

 middle of the basal portion it has internally a distinct lobe, about 2 m.m. in 

 length, which in its situation strictly speaking lies between the shell and 

 the neck lobe ; but as it becomes reflected with its edge over the shell, it 

 has to be regarded as the representant of the left shell lobe. The lower 

 portion of the left neck lobe is only a thickened swelling, extending as a nar- 

 row inner rim of the edge of the mantle to near the umbilicus. Both the 

 right and left neck lobe have a large black spot, in continuation of the later- 

 al black bands of the back. 



The general anatomy does not differ in any essential point from that of 

 i2. ancejps, as briefly noticed by me in Journ, A. S. B., Vol. xl, pt. II, 1871, 

 p. 233, pi. xvii, fig. 1. 



The jaw is semilunar, perfectly smooth, with obtusely rounded corners, 

 and a slight rounded projection in the centre of the concave edge ; it is about 

 1*5 m.m. broad. 



The length of the radula is about 4*5, and its breadth above 1*5 m.m. ; 

 it is composed of about 105 transverse, nearly straight rows of teeth, there 

 being about 121 teeth in each row. The form of the teeth again very close- 

 ly resembles that of Bot. anceps, (loc. cit.). All the points extend beyond 

 the upper edge of the basal plate ; the central is somewhat widened below 



