The Washington herald., 1909-03-21

ed shell. but as the adult condition IS
reached Il cements TO the shell branches
OF coral or other shells. or both. until
AT length ali means OF communication
with the exterior is by means Of the
siphonal canal alone. the aperture being
completely closed. What is the cause OF
this peculiar self-inmurement no one has
yet been able 10 decide. Another snter-
esting genus is MagilUs. the species OF
which all belong 10 the Eastern seas. and
III Is an excellent example Of that de-
generacy which occurs in certain mol
lusks- The young Magilus begins life as
a well behaved mOllusk. with a regular
spiral she'll but shortly Il settles down
on some growing coral, and then a race
begins between the two slow growing
forms II the mollusk kept quiet and
grew no further a short tine would suf-
nee 70 completely envel0p It In the stony
coral: but as soon as he is partly COW
cred the whOrls OF the shell leave their
spiral course. and grow out as an irreg-
ular tube. As the coral grows new ad-
oltlons are made to the shell, and the
Eeck-and-neck race is kept uD until one
or the other dies. After the tube be-
comes too long for the moEusk he leaves
the spiral portion and comes out TO live
IN the outer straight tube. filling up the
deserted whOrls with solid deposit OF
aime.
In Sea UrehIns' Spine.
The sea urchin IS perfected by a bony
envelop. and this IS covered with numer-
Gus sharp spines which project in all d.
rections Strange to relate. a small mol
lusk frequently houows out the interior
OF one Of the spines and uses il as a
home, thus providing for as own safety.
.as but few denizens Of the seas would be
hardy enough 70 attack the armored sea
urchin
Along the shores Of the North Allan
tic Ocean Is found a worm (Phascolosoma
coementarium), which takes possession
.of dead shell Of some small moHusk
Ike the hermit crab. but as the aperture
lis always too large for its body. II builds
out the rim OF :he aperture until only
IA small, round opening IS left. through
which the worm can stretch forth the
anterior extremity OF its body OF with
draw into the shell * has approprsated
Tor It's dwelling. II lives permanently IN
rs borrowed home. dragging il about by
the powerful COntraCtlOns OF its BODY
The material with which the worm so
shllfully patches out the shell SO ss 70
constrlct the mouth thereof Is hard and
durable composition OF sand and mud
.cemented together by a secretion Of the
animal. w. the worm grows too large
Tor Its habitati0n. iSstea5 Of exchanging
II Tor larger shell. as do the hermit
crabs. u gradually extends lts tube out
ward from the mouth OF the shell.
She'll Home for Worm.
In Indian seas are frequently dredgea
little solitary coraIs. These corals are
shaped something Ike small. thick
disks, and IN the base OF them there IS
usually embedded and concealed q dead
mollusk shell which serves as a home
for an active little worm. This arrange
ment Is Of mutual advantage as the
worm. BY thrustlng out one end OF frs
muscular body as a lever. IS able 10 vrhislz
itself and the coral about from place 10
place.
The large jelly fishes. which are found
In almost all seas, and which float AZ
or near the surface in almost countless
numbers. shelter many marine animals
under their umbrella and am0nu --.7fr
numerous tentacies. A small Caranx
nsn. numerous crustdceans. several spe-
~t'H VA AAp42-1A1s d-4- strange 10 rnLafa
even other jelly fishes. find refuge under
this floating house. One OF the most rr1ri-
Gus or these denizens Is a little white
shrimp with enormous lustrous gree,
eyes. which lives and rears its family
In the sheltertng arms OF sts host As re
Jelly hsh kills more food than IL can de-
YOUR, Jne shrimp lives on the remnants
In Last Indian seas branching zoo
phyte. creatures resembling the dead mems
fingers OF our New England coast. are
common This animal runs what might
be termed lodging house as hidden
among Its numerous bright pink branches
may be found many species OF crusta-
ceshs' n every instance the lodger being
colored similarly 10 It's host. and 50 lo-9
as u remains quiet IS perfectly invisible
70 its numerous enemies. The sea NV
which IS striped In alternate hands ~
yellow and purple. also gives shelter 10
similarly striped crustaceans and worms %