52 



POPULAR CONCHOLOGT. 



Family 1.— STROMBACEA. 



The animals of this family have the eyes large, placed 

 on stalks ; the tentacula springing from the middle of 

 the stalks, or not present ; the foot is not adapted for 

 crawling, but is used for springing. The shell has the 

 aperture sinuated below, near the canal, which is often 

 lengthened, and turned to the left ; the outer lip is 

 winged, or in the form of claws in the mature shell. All 

 the genera are marine. 



Pteroceras. Lam. — Shell oblong ; spire small ; 

 mouth terminated by a rather long canal ; 

 left lip ridged, right lip dilated in the 

 adult into several claws, and having a sinus 

 near the canal ; operculum horny. Animal de- 

 scribed in the family. — 10 species.* 



The number of claws varies in different 

 species ; the Pteroceras millipeda has a great 

 many, but they are small : in others they are * 

 straight, or nearly so, and smooth ; whilst Pteroceras mgosa. 

 many of them have these appendages very much curved. 



There is much singularity in the growth of these shells, 

 and the appearance they present at various periods is 

 strikingly different. In the young state of the animal 

 the shell has no claws, and these gradually make their 

 appearance, at first in the form of short and open canals, 

 which by degrees assume the length and curve of the 

 adult and completed shell, and eventually are closed up 

 with shelly matter and become solidified. 



Nearly all the species are inhabitants of the Indian 

 Ocean, and many of them exhibit the most beautiful 



* Reeve's Iconica. 



