No. I (191 7) EDIBLE MOLLUSCS 2\ 



restricted — it requires a cleaner habitat than M. casta and a strong 

 tidal current over the bed where it lives. Hence it is usually found 

 near the entrance to lagoons, where the tidal flow is great. 

 Spawning occurs about the beginning of September at Tuticorin, 

 probably also about May. 



The shell exhibits considerable variation in colouring ; usually, 

 apart from the postero-dorsal and umbonar regions, it exhibits 

 no banding, but in a few (Tuticorin) there are very broad ill-defined 

 radiating bands of a somewhat livid brown colour extending 

 from the ventral margin to half way to the umbo. The umbo 

 nearly always shows considerable colouring but this is extremely 

 variable and no two shells are exactly alike in this respect. Most 

 frequently a minute brownish speckling can be made out, either 

 alone or associated with a more conspicuous and extensive zoning 

 in a livid tint; in others this speckling resolves itself into a more 

 distinct colouring of chevron-shaped chestnut markings, which 

 may coalesce either into short rays or into concentric zones, never 

 spreading far beyond the umbo. 



The Black Clam— Velorita cochinensis (Hanley). 



Malayalam — Kar cntiit/iii. 



This small thick-shelled clam is found only in west coast 

 estuarine backwaters, where it is associated with the common 

 clani (Mcretrix casta ovum). Its shell is ribbed concentrically and 

 covered by a coarse thick black periostracum which is frequently 

 worn away by corrosion at the umbo, showing the whitish 

 shell beneath. The interior is characteristically pale pink in 

 tint. This clam can survive the prevalence of fresh-water con- 

 ditions longer than the common clam ; it was originally, I believe, 

 a fresh-water species, and its presence in quantity in estuarine 

 backwaters, subject during a considerable portion of the year to 

 brackish water conditions, indicates a marked change in its habits 

 and an acquired tolerance for saline conditions. It is used bj* the 

 same people as eat the common clam and its valves are also employed 

 in lime-burning in Malabar. It is not nearly so abundant as 

 Mcretrix casta ovum ; its habitat is usually further distant from the 

 sea than that of the latter species. 



The shell seldom exceeds 40 mm. in length. 



