When first visited at about half-tide, the majority of the 

 oysters lay in water not more than one foot and a quarter in 

 depth. The higher bunches' were actually awash, and on a later 

 visit, which coincided with the time of low-tide, a considerable 

 number were wholly uncovered. 



The oysters in this bed are characteristically elongate, long 

 and narrow or sub-spatulate in form and of remarkably regular 

 growth habit. They tend to segregate into clusters varying 

 from three and four individuals in each to massive clumps of 

 treble these numbers. Towards the higher parts of the patches 

 and especially towards the centres, the clumps are closely 

 crowded, gradually thinning out till, along the margins, the 

 clusters are found to consist of a very limited number of indi- 

 viduals and to be sparsely scattered over the bottom. It is 

 noteworthy that the density of population is in inverse ratio to 

 the depth of water — the oysters crowd the shallower parts and 

 become scarce and ultimately disappear as the water deepens. 

 A tendency to grow upwards, to raise the ventral margin by 

 growth towards the surface of the water, is most strongly 

 developed and accounts for the marked dorso- ventral elongation 

 of the shell. Another notable feature characterising growth ;is 

 the habit of these oysters to retain their own individuality in 

 the clusters ; for each to keep the greater portion of its shell 

 free from cohesion with those of its neighbours, due to a slight 

 amount of radial divergence in the direction of growth among 

 the oysters of each group. 



The latter habit produces very serviceable clusters, readily 

 separable into units, as the area of mutual cohesion is small 

 and limited to the massive dorsal region of the convex valve. 

 The joint made by the adherent surfaces is also imperfect, 

 rendered weak by the muddy scum present on one valve when 

 the other was in course of becoming attached to it. 



The only cultch existing on this bed consists of the dead 

 shells of former oyster generations. The bottom is very muddy 

 both on the bed and for a long distance in every direc- 

 tion around. Deeper water, up to 1- and 2| feet, is found 

 along each side of the bed and the probability is that the 

 elongate shoal which forms the basis of the bed has arisen by 

 accretion of the shells of successive generations of oysters ; a 

 gradual accumulation of hard material has occurred and provides 

 from generation to generation the only foot-holds or landing 

 places in a sea of surrounding mud, for successive broods of 

 oysters. 



The valves of these oysters are slimy to the touch, and have 

 the appearance of being encrusted with a thin muddy felting. 



