5< s ADDITIONS TO THE TASMANIA MOLLUSCAN FAUNA. 



but deep umbilicus. The canal forms a deep furrow, 

 bordered by sharp, raised edges, the whole raised 

 on a distinct ridge, which surrounds the shell about 

 midway between the suture and the periphery; on 



the lower side there is a smooth, depressed area. 

 The strong sharp ribs begin below this area, and 

 continue round the whorl to enter the umbilicus. 

 Above the furrow raised curved ribs roughly corre- 

 spond to those below; they continue uninterrupted 

 from the central ridge to the suture. 'Idle spaces 

 between these ribs are cancellated by six to eight 

 spiral keels, much smaller than the ribs, and not 

 passing over them. These spirals continue between 

 the lower ribs, passing over the upper part of them, 

 there giving them a crested appearance. All these 

 spirals are irregularly spaced. The apex of \]/ 2 

 turns is squared by a beaded ridge, and is sunken 

 below the level of the adult whorls. The mouth is 

 well defined by a continuous narrow margin ; the 

 slit is open, deep, and of moderate width. Whorls 

 two, exclusive of the apex. Colour, yellowish white. 

 Greatest diameter, \ l / 2 ; least, 1*4 ; height, i mill. 

 Habitat : — Frederick Henry Bay ; a few specimens 

 in kelp roots. It has a superficial resemblance to 

 Schismope beddomei (Petterd), but the ribs are 

 more numerous and continuous, and with strong 

 spirals, and it is a larger shell, and a true Scissu- 

 rella. Scissurella coronata (Watson), Challenger 

 report, page 114, seems a near ally. Figs. 4 and 5. 

 Type in Tasmanian Museum. 



