239 



thickened aperture appears only to exist in adult spe- 

 cimens of this genus. The usual length of the shell 

 is about two inches; but the writer has seen a gigan- 

 tic example measuring upwards of four inches. The 

 following species were all Lamarck had seen, but 

 several others are known in this country. The spe- 

 cific name of the type of this genus Lamarck has 

 changed from Stramineus toNodulosa. 



Struthiolaria nodulosa Struthiolaria crenulata. 



RANELLA. 



MUREX RETICULARIS. LinnCBUS. 



Mart.4 7 t.l2Syf.l22S. 



Mawe's Linn, plate 2§yfig. 5. 



Intermediate as this genus may be considered in 

 some respects between the G. Struthiolaria and G. 

 Murex, it naturally forms a distinct division, in con- 

 sequence of the singular position of the varices, or 

 thickened bands. — When the growth of the animal 

 requires an addition to its habitation, a portion of its 

 body, equal to the semi-circumference of the shell, 

 is protruded and left exposed, remaining stationary 

 till the additional half turn to the shell is completed : 

 and as the animal never adds to the capacity of the 

 whorls on either side, a depressed appearance is 



