122 DONACID A. 
DONACID. 
If this family had only consisted of the genus Donax, we 
would have united it to the Tellinide; but as it is conjoined to 
Ervilia, a more aberrant genus, we adopt it. The siphons 
appear to be shorter than in the Tellinide, and their cilia of a 
more complicated structure; the dentition is also less simple. 
There are only three undoubted British species, two m Donaz, 
D. anatinus and D. politus —the D. trunculus is probably 
exotic—and one in Frvilia, the LE. castanea. 
DONAX, Linneus. 
D. anatinus, Lamarck. 
D. anatinus, Brit. Moll. i. p. 332, pl. 21. f. 4, 5,65 (animal) pl. K. f. 7. 
Animal elongated, of a purplish-red or yellow ; mantle open 
on the ventral range, with double margins, the one short, with 
sinuated or scalloped edges; the other and outer is clothed 
with three rows of frmge, the two imner beig two sizes of 
moniliform white beads ; the outermost or third row has short, 
close-set, fine filaments of similar colour, altogether presenting 
a very elegant appearance. The siphons are of the same 
length, and, when fully exserted, are not more than half an 
inch; they do not put on a cylindrical aspect, but appear 
laterally compressed ; they are separate from the bases, and 
taper gradually to their terminations, which are bordered 
with very pale orange colour; the anal siphon is rather the 
smallest, and fwmished with about six white cirrhi; the 
branchial has 8-10 longer ones, which are fimbriated at the 
sides, besides plain ones interspersed; when the cirrhi are 
withdrawn, the terminations of the tubes have a truncate and 
naked aspect; a good lens must be used to see their minute 
developments. The foot is yellow or orange, especially when 
the animal has been immersed in hot water, very large, flat, 
bevelled toa sharp edge and lanceolate point when fully 
