240 
POPULAR SCIENCE REVIEW. 
THE ANATOMY OF THE RIVER-MUSSEL. 
Br JOHN C. GALTON, M.A. (Oxon) F.L.S. 
Lecturer on Comparative Anatomy at Charing-Cross Hospital.] 
[PLATE LXII.] 
“ Molluscorum scilicet testas inhabitantium anatomiam instituere, eorum- 
que internam structuram, partium formam et compagem, situs, nexus, atque 
usus declarare ; sive, ut verbo complectar, eorum zoologiam ac physiologiam 
simul persequi, opus certe pro rei dignitate eximium atque praestantissimum, 
prout est ceterorum omnium intricatissimum atque difficillimum.” — Poli. 
I N the Popular Science Review for April 1869, the leading 
characters of the great sub-kingdom Mollusca were ably 
sketched by Mr. St. George Mivart, F.R.S., and illustrated by 
the anatomy of the cuttle-fish. In the present article it is 
proposed to give an account, as concise and accurate as possible, 
of the structure and zoological affinities of one of the classes 
of the above sub-kingdom, namely, the Lamellibranchiata (leaf- 
gilled molluscs), as the type of which the common river-mussel * 
(. Anodonta cygnea) has been chosen. 
The Lamellibranchs are the only representatives of one of 
the two divisions into which, according to Professor Huxley 
(Hunterian Lectures , 1868), the Mollusca maybe conveniently 
divided, namely, the Anodontophora , or those which are de- 
void of any “ odontophore,” or tooth-bearing tongue ; the 
Odontophora comprising the rest of the Mollusca, such as the 
snails and slugs which breathe by means of gills or of a pul- 
monary sac, the cuttle-fishes, and the oceanic “ sea-butterflies,” 
certain of which, as the Clio Borealis , form the principal part 
of the food of the baleen-whales. 
• The various species of river-mussel, of which Anodonta cygnea, Unio 
tnmidun, U. pictomm , and U. margaritifer are British representatives, have 
been classed together in a family termed, by poetical license, “ Naiades” — 
river-nymphs. If a river-mussel shared our perplexity, it would doubtless 
exclaim, in the language of Keats : — 
“ Why it i3 thus, one knows in heaven above : 
But, a poor Naiad, I guess not.” 
