ERRATUM 



NOTE UPON THE IDENTIFICATION OF THE EDIBLE OYSTERS OF 



OKHAMANDAL. 



The rock oysters whicli densely crowd the surfaces of the rocks about half tide 

 level at Poshetra Point were wrongly identified in Part I, pp. 22 and 23. This species 

 appears really to be the Ostrea cucullata of Born and of Lamarck. 



Its main distinguishing characters are as follows : OutUne roughly oval ; the left 

 valve extensively attached, the cavity deep and cup-shaped, with a sacciform extension 

 into the hollow beak region of the hinge, which is moderately elongated in freely-grown 

 individuals ; the edges of this valve have a distinct tendency to grow upwards. Ex- 

 ternally the left valve is folded into deep ridges passing radially outwards from the 

 hinge and ending in a sharply dentate edge which interlocks closely with the edge of 

 the upper or right valve. The latter is flattened and opercular in form. The muscle 

 scars are normally purplish-black in tint, sometimes brown, rarely white. Very 

 characteristic is a row of closely-set elongated denticulations seen a short distance 

 inwards from the margin on the inner surface of the upper valve ; these fit into a corre- 

 sponding series of furrows in the lower valve. Externally the shell is tinted an opaque 

 pinkish-purple. Internally it is white, margined with purple or black. The size is 

 generally small, seldom exceeding three inches in length. 



The true identity of the fine edible oyster found on the muddy bottom of Aramra 

 Creek and named tentatively 0.' cucullata in Part I, p. 22, is somewhat doubtful. It 

 is certainly not 0. cucullata, as that is the name of the small rock-oyster above described. 

 In general form and in habit it closely approximates to the common estuarine oyster 

 of South India, a species which appears to be identical with or extremely closely related 

 to Ostrea virginiana, Gmelin, the most abundant oyster of the Atlantic Coast of North 

 America. The Kattiawar oyster differs from both these forms by the possession of 

 white muscle scars, which in both 0. virginiana and the South Indian form are con- 

 sistexitly purphsh black. It is the same species as is found in local abundance in the 

 muddy creeks of the Sind and Kutch coasts. Its shell sometimes attains a remarkable 

 size ; I have one valve 14 inches long. The thickness is also characteristically great. 

 It wiH probably be found to be Ostrea gryphoides, Schlotheim, or a variety thereof. 



Very Uttle is known at present concerning the number and relationship of the 

 different Ostreids of Indian waters, and their nomenclature is in a state of considerable 



