540 
POPULAR SCIENCE REVIEW. 
two orders are characterized by peculiarities of the segments which compose 
the annelid’s body : thus, in the Errantes, all the segments are alike, but 
in the Sedentaires the body may be regarded as being made up of a series 
of segments, or sets of segments of different kinds. 
Composition of Oyster Liquoi\ — M. Payen’s observations upon this point 
are worthy at least of the attention of oyster-eating savants. The liquid 
found in the substance of the oyster and among its tissues is not simply 
sea-water, for it contains less salt and more organic matter. When shaken 
with ether, it deposits some albuminous material containing 875 per cent, of 
nitrogen. The hquor probably plays some part in the nourishment of the 
oyster, the weight of which is nearly always equal to that of the liquid. The 
following is the composition of the latter : — 
Water 95’888 
Salts 3 ‘022 
Nitrogenized matter 0’560 
Non-nitrogenized ditto 0*529 
Subjoined are the relative weights of shells, animal substance, and liquor, 
in a dozen oysters weighing 1,482 grammes ; — 
Shells 1209 
Flesh 112 
Liquor 102 
By converting the nitrogen of the oyster into nutritive matter, M. Payen 
calculates that a dozen oysters represent in nitrogenized matter only the 
tenth of a man’s ration. — Vide The Chemical News, April 28th. 
M. de Quatrefages and M. Claparede. — While the ink with which we have 
written the above account is drying, we have received from M. Quatrefages 
a copy of his memoir on the classification of Annehds, with an appendix ex- 
plaining away some of the objections which the savant of Geneva has raised 
to his views. We give a translation of M. de Quatrefages’ remarks. “ The 
appeal which I made to my fellow-workers in publishing in the Comptes 
Rendus the paper of which the present is a reprint, has elicited some written 
observations from M. Claparede, which he has been good enough to forward 
to me with his Glanures Zootomiques, and an article published in the 
BibUotheque Universelle de Geneve for April, 1865. I received these important 
documents at the moment I was correcting the proofs of my memoir. 
Pressed by time and inexorable business, I was unable to give them that 
study and serious consideration which they deserved ; the ‘ Glanures ’ 
especially, for it contains a great number of new facts which ought 
to have been taken into account, and which I shall certainly deal 
with as it deserves in my future work. The article in the BibUotheque 
is a critical essay. The writer has appreciated my views and their appli- 
cation, and has added comments upon certain facts.” These strictures M. de 
Quatrefages then proceeds to reply to in fifteen paragraphs, which are far 
too long for analysis here. We may however remark that those interested 
in the classification of Annelids will find that M. Quatrefages has the best of 
the discussion, both in fact and in courtesy. 
