122 TEREDIDZ. 
tubes (siphons), mostly of unequal length. The larger tube 
(siphon) takes in infusoria or similar animalcules, which consti- 
tute the food of the Teredo, as well as imbibes water charged 
with air for the purpose of respiration and keeping the whole 
fabric moist; while the smaller tube is employed to eject the 
water which has been exhausted or deprived of its aeriferous 
qualities, and also serves to get rid of the woody pulp that is 
excavated by the Teredo. Both tubes form a kind of hydraulic 
machine. At the base of each lies one of the paddles, often 
termed ‘pallets,’ and which may be translated into scientific 
language as ‘claustra.’ When the Teredo is alarmed or not 
feeding, it withdraws its tubes into the neck of its sheath or 
shelly cylinder; and the pallets, which had been previously kept 
pressed against the sides, then spring forward and close the 
opening, so as to form an efficient barrier against all foes, whether 
crustacea or annelids. This complicated animal mechanism is 
entirely enclosed in the sheath or cylinder above mentioned, 
which is secreted by the mantle, and varies considerably in 
thickness and extent. The inside of the sheath is, at its outer 
or narrower end, divided into short strips or ledges, arranged 
in an imbricated fashion ; the last-formed of these ledges serves 
asa point d’appui for the blades of the paddles, and it greatly 
assists the Teredo in closely shutting its doors. The whole of 
what I have above endeavored to describe is found only within 
some hard vegetable substance, either the hull of a vessel or boat, 
a harbor pile, a shipping-stage, a floating tree or the roots of one 
growing on the banks of an estuarine river. The food of the 
Teredo consists entirely of minute organisms, that are introduced 
with the water into the incurrent or branchial tube, and it does not 
consume the wood as any part of its nourishment. Nor do I 
believe that the eroded material undergoes any chemical change, 
either in the stomach of the Teredo or in the passage outwards 
through the intestine, although in the latter receptacle it is 
closely compressed. When it is voided or expelled by the 
excurrent tube, and separated in the water, it becomes a floccu- 
lent mass of pulp, like that of paper, composed of extremely 
minute and fine particles of an irregular size and shape, but still 
retaining its fibrous structure. It does not exhibit any appear- 
ance of having been digested.” 
 CALOBATES, Gould, 1862. Siphonal pallets large, long, stilt- 
shaped, siphons adherent, only becoming free at the tips. 7. 
furcelloides, Gray. 2sp. Burmack, Australia. 
NausiTorA, Wright, 1864. Siphonal pallets, outer surface 
convex, covered with thick scale-like striz, inner flat or slightly - 
concave. N. Dunlopi (fresh-water, India). 2sp. Burrowing in 
wood. Bengal, Australia. 
Lyropus, Gould. This name is given for a small American 
