FAMILY 4. TUBISPIRACEA. 43 
Family 4. TUBISPIRACEA. 
Testa tubulosa, irregulariter contorta; spira laxd, interdum fissura per 
totam longitudinem decurrente. Animal operculo corneo instruc- 
tum. 
Linnzus and his predecessors, who were but little acquainted with the 
animal inhabitants of tubular shells, assigned nearly the whole of them, 
without speculating upon what might be their nature or anatomy, to one 
common genus, Serpula. ‘These tubular shells were, however, at length 
found to contain animals of varied organization ; his Serpula aquaria, for 
example, was found to be an acephalous mollusk, Aspergillum ; his Ser- 
puleé anguina and vermetus to be true cervicobranchiate Gasteropoda, 
forming the types of the two genera, Siliquaria and Vermetus, associated 
in this family ; whilst the rest of them, distinguished by subsequent au- 
thors as the genera Serpula, Spirorbis, Galiolaria, Vermilia, &c., are found 
to belong to another division of the animal kingdom, the Awwezipzs. 
The shell of the Tubispiracea may be described as being tubular, and 
irregularly twisted into a loose spire, with sometimes a slit running 
throughout its entire length. The animal is furnished with a horny 
operculum. 
The two following genera may be referred to this family : 
SILIQUARIA. VERMETUS. 
SILIQUARIA, Bruguiere. 
Testa tubulosa, subcylindrica, irregulariter contorta, posticé plus minusve 
attenuata, in spiram laxé producta; anticé evolutior, extremitate 
GE 
