CERAPUS. 
453 
Say, in his character of the genus, described the 
flagella to the antennae as consisting of a single joint, 
a mode of expression not unusual among authors. 
Milne Edwards consequently established his genera 
Ericthonius and Cerapodina in consequence of the antennae 
terminating in multi-articulate flagella. The former was 
founded upon an animal examined by the author, the 
latter upon Templeton’s inaccurate figure of Cerapus 
abditus. Professor Dana has likewise founded his genus 
Pyctilus upon a misconception of the figure of Ericthonius 
difformis , illustrative of M. Edward’s description of that 
genus, which the artist has drawn with the coxa of the 
first pair of legs fused with the body of the animal, 
a circumstance not alluded to in the author’s description, 
and one that Professor Milne Edwards informs us was 
an error of his draughtsman. It is for these reasons 
that we are led to consider that these several genera are, 
together with Dercotho'e* only synonyms of Cerapus . 
The species of this genus are not very numerous, but 
they have a tolerably wide geographical range. They 
exist mostly in the warm temperate zones. The form of 
their abodes appears from Say and Templeton to be 
membraneous tubes; the former states them to be un- 
attached to any substance, and carried by the free will of 
the animal as it swims or walks about — a fact which has 
not been corroborated by any subsequent observer. Mr. 
Stimpson,inhis “Marine Invertebrata of Grand Manan,” 
p. 47, writing of Cerapus rubricornis, says, “it inhabits 
flexible tubes, of sizes corresponding to that of the 
individuals, composed of fine mud and some animal 
cement by which it is agglutinated. These tubes are 
generally adherent for about one-half the length and 
closed below. They are usually found in large groups 
Vide page 459. 
