No. 6 (lQ2l) COMMON MOLLUSCS OF SOUTH INDLA 



131 



knobs ; like the true chank strong ridges are present on the colum- 

 ella. It is found on rocky ground, rarely in the Gulf of Mannar, 

 more frequently in the Laccadive Islands. 



Mclongcna vespertilio is common at the mouths of backwaters on 

 the East Coast ; it may often be found crawling in the shallows near 

 the bar at Ennur. It has a distinct resemblance to the Andaman 

 variety of the chank, having a well marked shoulder from which 

 short conical knobs project at regular intervals. The spire is short 

 and the canal long. The surface is covered with a velvety yellowish- 

 brown periostracum. There are no plicae on the columella. 



The Fasciolariidac often grow to a great size, particularly so in 



the case of Fasciohiria gigantea 

 which may reach a length of two 

 feet and Fitsus colossus and F. 

 proboscidalis. In Indian waters 

 the largest species is the 



Knobbed Chank, Fasdolaria 



trapezium, a chank-like shell, 

 often 4 inches long, with a short 

 spire, armed with stout knobs. 

 The columella lip anteriorly is 

 ridged with several oblique folds. 

 A thick brown periostracum pro- 

 tects the shell. It lives on the 

 same ground as the true chank, 

 but in comparison is few in 

 numbers; the chank divers of 

 Tuticorin bring it ashore when 

 they find it and eat the flesh. 

 The eggs are laid in capsules 

 where the young undergo their 

 development. A smaller species 

 is the dark brown F. filamcutosa, with sculpturing reduced to faint 

 spiral ribbing and the merest vestiges of knobbing on the shoulder. 

 Much more elegant is our common Spindle-Shell. Fusus 

 coins. No shell could be more truly named for it is typically fusi- 

 form or spindle-shaped, the spire drawn out very long and the 

 canal extremely elongated and narrow. The body whorl is com- 

 paratively small; the well-defined angular shoulder to the whorls 



Fic;. 17. Egg cases of a large Gastro- 

 pod, probably Fasciolariatrapeziion. 

 upon a dtacl chank shell. 



