DELPHINULA. SOLARIUM. 77 



The aperture is nearly round, the whorls gibbous, 

 or inflated with carinated ribs : the colour is usually 

 pink or white. It is very costly. (Plate 9.) 

 These shells are brought from the East Indies. 



"The fossil species are very elegant: they 

 are found in the strata above the chalk. 



"Two other species are common, S. commu- 

 nis and *S^. lamellosa. The first is a British 

 species, and is called the false TVentletrap. 



" The shells of the genus Delphinula are 

 solid, thick, somewhat discoid, often armed with 

 spines, without any apparent columella. The 

 recent species inhabit the Indian Ocean. There 

 are several fossil species oi Delpli Inula. 



'' The Turhlnacea family contains many genera, 

 with which you will soon become familiar. I be- 

 lieve you are already acquainted with this shell, 

 which, from the time it was first known to col- 

 lectors, has always been celebrated for beauty. 

 It is now called Solarium perspectivum. 

 (Plate 9.) The large, spiral, crenated umbilicus 

 is its great peculiarity. The French call the 

 shell Cadran, dlaL In its natural state the shell 

 is covered with an epidermis. There are a few- 

 fossil species, one in the oolite of our own country. 

 The English name is staircase trochus. 



" The genera of Turhlnacea are, 

 Solarium Troch us. 



