ANOMIA. 43 
are never exactly of the same size, nor do they preserve their 
relative positions in any of the varieties, in consequence of the 
animal dividing the muscular mass into three fasciculi of fibres, 
varying in quantity, thus altering the shape and relative distance 
of one portion from the other; therefore these impressions are 
of little distinctive value. 
Finally, as regards the animal, it may be observed, that in 
this singular unsymmetrical genus, even its organs display, 
hike the shell, varieties of form; this arises from the entire 
animal being deposited im the convex valve; it only rests on 
the flat one, and the organs, in consequence, vary with the 
ever-varying figure of the upper valve. 
I will now make some remarks on the various markings 
and aspects of the shells of the so-called British species, of 
which I have examined above a thousand. And as regards 
their general shape, they vary from all grades of subcircularity 
to every subtriangular form. I have seen on the same Pecten, 
on the shells of which genus the Anomie are oftener fixed 
than on any other, two individuals of the typical dirty-white 
A. ephippium, the one displaying its strictly squamous cha- 
racter, and marked not only with ribs, but the vaulted and 
arched spines of the Pecten; the other, in contact, without a 
rib or spine, and only showing the regular squamee of increase. 
I have also seen the A. ephippium with half the transverse 
portion of the shell of a perfectly squamous character, and the 
basal half ribbed and spiny, and vice versd. The same inci- 
dents are seen in the rosy purplish A. cepa and bright yellow 
A, electrica of British authors, which axe mere deviations of 
colour from the type. 
As for A. striata, otherwise the A. undulata of some authors, 
which is certainly the most aberrant form of the A. ephippium, 
the distinctness of which has been insisted on from the iri- 
descent green colour of the inside of its valves, the radiating 
muscular impressions and the intense vermilion of the ani- 
mal, I have to observe that in young specimens, of one and a 
half inch diameter, having the anastomosing radiating striz 
found on the smooth insides of the Pecten maximus, I have 
noticed these characters to be by no means constant, having 
