Filial duties and domestic bereavements caused another two years’ delay. Banished to the seaside, and the pen prohibited during the winter of 1874-75, I had almost despaired of turning my studies to account, when a new impulse arrived in the shape of a note from the editor of _Chambers’s Journal_, begging to know if my ‘work on the Ophidia was out, and by whom published’? My ‘work on the Ophidia’? Could that mean my poor, despised little book that had been long ago submitted among others to those Edinburgh publishers? _My work on the Ophidia!_ I began to get better from that day; and from that date, March 1875, I have had the inexpressible pleasure and privilege of including among my kindest and most sympathetic ophiological friends, the Editor of that popular journal. On the Ophidia, he entrusted me with work in various directions, encouraged by which I again returned to town, and to the Zoological Gardens. If I am so fortunate as to afford instruction or entertainment in the following pages, my readers will join me in congratulating ourselves on the possession of so large and valuable a zoological collection as that in the Regent’s Park, without which this book could not have been attempted. And I may embrace this opportunity of expressing my sincere thanks to the President and Council of the Zoological Society for the privileges and facilities afforded me at their Gardens, where not only the Reptilium but the annual series of zoological lectures there, given by the first biologists of the day, have been of inexpressible use to me.