To Sir John Richardson.

October 31, 1850.

I regret very much that in consequence of our being ordered to be paid off at Chatham, instead of Portsmouth, as we always hoped and expected, I shall be unable to submit to your inspection the zoological notes and drawings which I have made during our cruise.  They are somewhat numerous (over 180 sheets of drawings), and I hope not altogether valueless, since they have been made with as great care and attention as I am master of—­and with a microscope, such as has rarely, if ever, made a voyage round the world before.  A further reason for indulging in this hope consists in the fact that they relate for the most part to animals hitherto very little known, whether from their rarity or from their perishable nature, and that they bear upon many curious physiological points.

I may thus classify and enumerate the observations I have made:—­

1.  Upon the organs of hearing and circulation in some of the transparent Crustacea, and upon the structure of certain of the lower forms of Crustacea.

2.  Upon some very remarkable new forms of Annelids, and especially upon the much contested genus Sagitta, which I have evidence to show is neither a Mollusc nor an Epizoon, but an Annelid.

3.  Upon the nervous system of certain Mollusca hitherto imperfectly described—­upon what appears to me to be an urinary organ in many of them—­and upon the structure of Firola and Atlanta, of which latter I have a pretty complete account.

4.  Upon two perfectly new (ordinally new) species of Ascidians.

5.  Upon Pyrosoma and Salpa.  The former has never been described (I think) since Savigny’s time, and he had only specimens preserved in spirits.  I have a great deal to add and alter.  Then as to Salpa, whose mode of generation has always been so great a bone of contention, I have a long series of observations and drawings which I have verified over and over again, and which, if correct, must give rise to quite a new view of the matter.  I may mention as an interesting fact that in these animals so low in the scale I have found a placental circulation, rudimentary indeed, but nevertheless a perfect model on a small scale of that which takes place in the mammalia.

6.  I have the materials for a monograph upon the Acalephae and Hydrostatic Acalephae.  I have examined very carefully more than forty genera of these animals—­many of them very rare, and some quite new.  But I paid comparatively little attention to the collection of new species, caring rather to come to some clear and definite idea as to the structure of those which had indeed been long known, but very little understood.  Unfortunately for science, but fortunately for me, this method appears to have been somewhat novel with observers of these animals, and consequently everywhere new and remarkable facts were to be had for the picking up.