272 Mr. Griffiths’s Description 
septum running down for eight or nine inches, forming it into 
two distinct tubes, inclosed within the outer one, from whence 
the animal throws out tentacula ; the substance of the shell is 
composed of layers having a fibrous and radiated appearance, 
covered externally with a pure white crust, and internally 
is of a yellow tinge ; the external surface is frequently inter- 
rupted in a transverse direction by a sudden increase of 
thickness, which probably indicates different stages in the 
growth of the shell, although they are at unequal distances, 
sometimes at six inches, at others four, in the same shell. 
These interruptions bear a rude and unfinished appearance, 
and do not extend into the radiated substance, but are merely 
on the outside shell, which has rather a smooth surface, but 
at the same time impressed with the irregularities of the sub- 
stance with which it was in contact. These shells all differ in 
thickness, some being not more than one-eighth of an inch, 
others full half an inch in substance ; many are nearly straight, 
others crooked and contorted. The internal surface is in 
general smooth, though in some of them covered with ex- 
crescences resembling tubercles, and without any indication of 
the animal having adhered to any part of it. 
It is the great length and size of these shells, which are 
the largest of the testacea of a tubular form yet discovered, 
and the division in the upper part, which constitute their 
principal peculiarities. I should add, that on their being broken 
in a transverse direction, the body of the shell between the 
inner surface and the outer crust, appears to resemble stalac- 
tites, and indeed they might easily be mistaken for them. 
By consulting Rumphius I found that my opinion of these 
tubes being entirely a new genus, was unfounded, for which,. 
