COOKE : MITBA BURNUPIANA, N.SP. 115 



longer. The callus is mucli more strongly developed, quite forming 

 an inner lip. The juncture of the callus above with the outer lip 

 stands out from the body-whorl, almost forming a posterior canal, 

 as it does not in circula. 



" The outer lip is thicker, less crenulate, and more polished. The 

 columellar plaits are more strongly developed, forming together a 

 triangular mass, with the upper plaits so much longer than the lower 

 that if a line be drawn from the tip of the fourth to that of the first 

 and extended upward it would reach the suture ; whereas in 

 circula it would strike the paries considerably to the left of the 

 suture. 



" The columella is not so much ' produced in the style of the 

 Fusidse '. 



" Although all the above distinctions may not be conspicuous 

 in the comparison of any two individuals of the two forms, enough 

 will always be found to enable the careful student to separate them 

 without hesitation. 



" Both forms, as found in Durban Bay, are a good deal short of 

 Kiener's length dimensions, i.e. about 27 mm. against 38 mm. As 

 both forms are found together, variation through environment is 

 barred. 



" The dimensions given with the above figure are those of the 

 enlarged drawings, not of the shells themselves." 



The actual dimensions of two specimens in my collection are : 



mm. 

 Total length of shell . . . hurnupiana 27 



,, ,, ... circula 26"5 



Breadth of shell at widest hurnupiana 10 



,, ,, ,, . . circula 7 



Length of spire hurnupiana 13 



„ ,, circula 15 



,, aperture . . . . hurnupiana 14 



,, ,, .... circula 11*5 



The type-specimen is placed in the British Museum (Natural 

 History). 



