EXPLANATION OF TERMS. 215 



Peduncle. The tubular support of some of the 

 Lepades. 



Pellucid. So clear that the light is seen through ; 

 from per, through, and lux, light. 



Plicated. Folded or plaited ; from plica, a fold. 



Punctured. Pricked or marked with small dots ; 

 from punct um, a point or dot. 



Patulous. Lying open or spreading ; from pat ere, 

 to lie open. 



Quincunx. Disposed alternately as in rows of 

 spots, when the spots of each row are 

 opposite to the space between two spots 

 of the next row ; from quin que five, and 

 unx, ounce, as the weight representing 

 five ounces was stamped thus :: 



Rotatory. Like a wheel ; from rota, a wheel. 



Rostrated. Having a beak, from rostrum, a beak. 



Retuse. Having the lower whorls of the spire 

 pressed into the body whorl, from re, 

 back, and tus us, beaten. 



Reversed. Applied to spiral shells, whose volu- 

 tions turn in the contrary direction to the 

 generality of shells, and which are also 

 called sinistral, or left handed, from 

 sinistra, the left hand. If when a shell 

 is placed on its base, with the front 

 facing the person looking at it, the 

 aperture is on the right side of the pil- 

 lar, the shell is said to be regular or 

 dextral, if the aperture is on the left 

 side of the pillar, it is said to be reversed 

 or sinistral. 



