Addi^ess of the President at the Annual Meeting. 
51 
number in N. varians, to 24, the least number in N. mufahilis ; 
and looking to the great capacity for variation shown by both 
forms, the probability seems to me to be decidedly in favour 
of their specific unity. 
Passing on now to the other papers which have been read 
since the last Anniversary, I come to my own 'On the Deve- 
lopment of the Embryo oi Purpura lapillns,' on which, of course, 
it is not for me to comment. 1 may, however, be permitted 
to make one or two remarks, in relation to the general subject, 
and the m ethodof the investigation ; — First, that it affords 
an example of what may be done with very simple means, 
since the greater part of the inquiry was ij^orked-out under 
single lenses, Mr. Quekett's dissecting-microscope having 
been the instrument chiefly employed, and the achromatic 
compound-microscope having only been occasionally resorted 
to for more minute examination and for verification. Secondly, 
that even a brief space of time may serve to do much, if it be 
well employed ; my whole sojourn at Tenby was less than a 
fortnight, and the greater part of several days was occupied in 
the search for living Foraminifera, which were the objects I 
had specially in view. Thirdly, that it is of great importance 
to obtain as many facts as possible, as a basis for reasoning; 
and to trust no more to hypothesis for the connection and expla- 
nation of those facts, than is absolutely necessary. The error 
of my predecessors lay in imperfect observation (the most 
important period in the developmental history ha.ing been 
passed-over by them), and in inventing a theory to fill up the 
hiatus, which proved not only to be fundamentally erroneous, 
but to have given a wrong colour (so to speak) to all their 
statements of fact. Now it happened to myself, that although 
I had seen quite enough to satisfy me that tJieir notion of tlie 
process was altogether erroneous, and had formed a decided 
opinion as to what was its real nature, I failed in obtaining 
that positive assurance of its truth which alone would have 
justified me in putting it forward as an ascertained fact, until 
the very last day of my researches ; when I had the good for- 
tune to alight upon a group of Purpura-capsules, at such a stage 
of development that almost every one of them contained young 
embryoes of : different sizes, attached to the conglomerate 
vitellus, and obviously ingesting its particles; and these I 
was able not only to observe for myself, but to exhibit to my 
friends, who had previously seemed doubtful how far my expla- 
nation of the mode in which the large embryoes were formed, 
was more to be trusted than that of my predecessors, J^M. 
Koren and Daniellsen. I would add that any one who has 
the opportunity of paying even a short visit to any shore, on 
e 2 
