1^> VARIATIONS IN NUMBERS AND HABITAT OF 



much depends on accident ; nor would it be fair to take 

 particular notice of what I have seen in places not visited 

 repeatedly, 



I think that some great changes were due to the very severe 

 winters experienced a few \'ears ago. For example, the number 

 of living individuals of the common Cavdium ediile previously 

 found near the mouth of the Crouch was very great ; after the 

 severe winter of 1894, which killed so many oysters, few could be 

 found alive, but an enormous number of dead shells were seen. 

 Also, previously, very fine specimens of the Gephyrian, 

 Priapulus caudatus, could be obtained from the mud of the Deben 

 near Waldringfield, but afterwards only comparatively small 

 individuals, as though the larger had been killed. It, however, 

 seems doubtful if this explanation will suffice in places where the 

 water is always tolerably deep As an example, I may say that 

 eight or ten years ago, in that part of the Deben, near Ramsholt, 

 called the Recks, 1 was able to collect by dredging fairly numer- 

 ous fine specimens of the beautiful purple Nudibranch, Eolis 

 covonata, but latterly I have not been able to obtain them, though 

 most anxious to do so. They have also become more rare in 

 other localities where I used to find them, as for example in the 

 Orwell at Pin Mill, and ofT Mersea, in what may be looked upon 

 an almost open sea. 



It seems difficult to understand what can have occurred to 

 influence such a large mass of sea water as in the Stour below 

 and above Harwich, but yet I have remarked considerable 

 changes during the last 10 or 12 years. I then found sundry 

 Nudibranchs, which I have not obtained for years and the 

 curious worm, Aphrodita aculeata, has become much more rare. 

 Good small specimens of Lo/i^o media were fairly common, but 

 latterly they have become more and more scarce. Both there 

 and in every locality in which I have trawled, the number of 

 specimens of Sepiola atlantica has also become less and less, year 

 after year, and, instead of catching dozens, I got only an odd one 

 now and then. What may possibly have been a distinct small 

 species of Sabella was at one time abundant in the Pye-fieet by 

 Mersea, but I have not seen it for some years. On the contrary 

 in 1899 I caught off Mersea some half score of what are probable 

 the young specimens of Sepia officinalis, not one of which I 

 had caught before anywhere along the coast. In some of the 



