Worms

British Museum (Natural History).

Instructions for Collectors:

No. 12.—WORMS.

Lettre

“

oe, BU a
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LONDON:
1915.
PRICE THREEPENCE.
(All rights reserved.)

Specimens intended for the Natural History Branch of the
British Museum should be sent to

THE BRITISH MUSEUM (NATURAL HISTORY), —
CROMWELL ROAD,
LONDON, 8.W.

All communications should be addressed to the DIRECTOR.

NOTE.—Boxes of specimens so addressed are not opened by
the Customs Officers at the Docks, but are forwarded to
the Museum under seal.

PRESENTED

BY

The Trustees

or

BRITISH MUSEUM.

——a |

C
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™

Instructions for Collecting

Worms.

INTRODUCTORY REMARKS.

On COLLECTING.

Tue term “ Worms,” as here used, embraces a great many animals
which bear very little resemblance to the popular conception of a
worm. Some little idea of their variety and of the situations in
which they are most likely to be found may be gathered from the
lists given below.

It will be seen that the parasitic groups are A 2 and 3, C, D, E,
and those mentioned on pp. 10-11.

The majority are internal parasites of vertebrate animals;
but their position in their hosts varies very greatly. Many
live in the alimentary canal, but many occur in other cavities and
organs of the body, eg. the heart, liver, lungs, kidneys, bladder,
body-cavity, nasal cavities, or even in the blood-vessels, bronchial
tubes, and among the muscles and connective tissue. Some of the
Trematodes and Leeches are external parasites of fishes and other
aquatic or amphibious animals, and may be found attached to their
skin, especially on the fins, or on the gills and in the cavity of the
mouth. Hence one must not be content merely to open the
intestines of an animal and make a hasty examination there, but all
parts of the animal ought to be inspected. Even the connective
tissue between the skin and flesh often contains parasites. Filarice
(Nematodes), for instance, often choose this situation, where they
lie coiled up in capsules or “cysts’’; and the larval forms of
various other parasites may be discovered in similar positions.
When found in the connective tissue or in the peritoneum covering
the internal organs and body-cavity, or in the walls of the stomach,
etc., it is advisable to cut out and preserve the cyst with a small
portion of the surrounding tissue.

It is worth while to collect all parasites seen, since it is often
only the most careful microscopic investigation that can determine
& species,

Some small Nematodes parasitic in the intestines, more
especially of birds, are so fine that they are difficult to see unless
some of the contents of the intestine or ceca are shaken up in salt
solution or water, when the little hair-like creatures can be picked
up with a needle, to which they adhere readily. For many

2

Nematodes it is a good plan to shake or stir up the intestinal
matter in a vessel of weak salt solution, and allow it to stand,
when the worms will sink to the bottom, and the dirty fluid can
be poured off. Clean fluid may then be added, and the process
repeated until the worms are clean and free from débris.

In collecting Tape-worms the intestine of the host should be
slit up with a pair of scissors (preferably blunt-ended) and the
contents scraped out gently with the back of a knife or scalpel.
The scraping ought to be so managed as to secure the heads of the
worms, which may be attached more or less firmly to the lining of
the intestine. If any are very firmly attached a small portion of
the intestine may be cut out round them, and placed with the

a b Cc d

FIGURE 1.
Portions of an adult Tapeworm, Taenia serrata, natural
size. a, the head (scolex) and some of the young
segments ; d, the most fully developed (gravid) segments,
near the hinder end of the worm: 3%, e, portions from
intermediate regions. [CESTODA.]

worms in a dish of weak salt solution, when by gentle persuasion,
by means of scalpel or needles, the worms may be made to loosen
their hold. In general, however, it is best to place the mass of
worms and ingested matter in a tall vessel of salt solution, any
floating lumps being broken up, and the worms then washed by
gentle “shaking, as directed on p. 22.

On LABELLING.

It is extremely important to label
all specimens fully.

The label bearing data as to the
host in which a _ parasite occurred,
its position in the host, the locality,
date, and any other Siseamiions made
at the time of collecting, is almost
as valuable as the specimen itself; a
specimen without its label is practically
useless. These remarks, of course,
apply to free-living forms as well as to
parasites—notes as to the position in
which they were found should always
be given. The method of preservation
used should also be stated. In addition
to the labels giving such information,
it is well to number the specimens, and to
keep a note-book with full notes of each
specimen or set of specimens opposite
its number.

In the case of parasites, the species
of the host (if known) should always
be given. If unknown, an accurate
description of it, and if possible a
drawing, will help greatly in the labour
of determination. In some cases (e.g.
small Fishes, Reptiles, Mammals, &c.) FIGURE 2.
it would be well to preserve the ip pra \ ey eo br a
host as well as_ the parasite, ing the hooks and two of the
giving it a corresponding label and ‘Suckers. From a Ee ea
number.*

Labels should» be written clearly with a soft lead pencil on
unsized paper, and placed in the preserving fluid with the
specimens. Ordinary imk will not do for this purpose, as it
will wash out. Certain kinds of waterproof Indian ink, however,
are good, if allowed to dry thoroughly before being placed in the
liquid. In some cases an additional label in ink may be placed
outside the bottle.

* Fishes, Amphibians, Reptiles, &c., are best preserved in spirit; in the
case of Birds and Mammals the skins must be preserved, and the skulls of
Mammals should be dried and labelled to correspond with the skins. (See
“« Instructions for Collectors,’”’ Nos. 3, 2, 1.)

4

SCIENTIFIC AND POPULAR NAMES OF THE CHIEF
GROUPS OF “ WORMS.”
A. PLATYHELMINTHES (Flat-worms). Including :—
1. TuRBELLARIA (Planarians).
2. TREMATODA (F'lukes).
3. Crsropa (Tape-worms).

B. NEMERTINEA (Long unsegmented worms, mostly marine).
C. NEMATODA (Thread-worms or Round-worms).

D. NEMATOMORPHA or GOR-
DIACEA (Hair-worms).

E. ACANTHOCEPHALA (Includ-
ing Echinorhynchus).

F. CHATOPODA (Bristle-worms).
Including :—

1. OuicocHmtTa (Earth-

worms and their allies).

2. PotycH@Ta (Marine
bristle-worms).

G. GEPHYRBEA.

H. HIRUDINEA (Leeches).
I. PHORONIDEA (Phoronis).
J

ENTEROPNEUSTA (Balano-
glossus).
Some of the distinguishing features
of the groups mentioned above are
outlined in the following

: : BRIEF SYNOPSIS, OF 2s
IGURE 5. ‘
Fasciola hepatica, the Liver-fluke CHIBF GROUPS OF WORMS.

toler mad onlargal spouse 2> A. PLAT YHEUMIN DEES
diameters. The veneuntnee ‘Ooimals of flattened shape, their
behind the mouth. In some yiscera not contained in a “ body-
related species it ag amnat? cavity.” The alimentary canal, which
is either simple or branched, has no
anus or vent. Mostly aquatic or parasitic ; exceptionally lving
on land in moist situations. These include :—
(1) TurBEeLLaRiA (see Fig. 14). Usually with soft, oval or
elongate, unsegmented body, covered with minute cilia, or vibratile

“hairs.” Mouth often in centre of ventral surface, or even further

5

back, with protrusible tubular pharynx. Alimentary canal simple
or much branched. Chiefly aquatic (marine and fresh-water) ;
some terrestrial, living in damp places, generally under logs or
stones,

(2) Tremaropa (e.g. Fasciola hepatica, the well-known Liver-
fluke of the Sheep.—See Fig. 3). Internal or external parasites ;
usually of oval shape. Unsegmented. With suckers and some-
times horny hooks for attachment to host. Alimentary canal
bifurcate, sometimes branched.

(3) Cestopa (eg. Tenia of various species, parasitic in man,
dog, etc.—See Figs. 1 and 2).

HKlongate parasitic creatures, of ribbon-like form, with a
rounded “ head”’ bearing suckers or hooks and suckers, followed by
a series of segments Increasing in size
posteriorly. The hinder segments are
generally full of eggs. The larval or
young forms (see Fig. 4) of these
worms are found as_ bladder-like
‘cysts’ of various sizes embedded in
the organs (e.g. the liver) of some
animal which is liable to be eaten by
their final host. Alimentary canal
absent in all stages.

{ Note—In collecting Tapeworms
great care must be faieen to find the
head (Figs. 1 and 2), which is very
minute and easily broken off, as it
may be attached firmly to the host’s
tissues. (See p. 2.) |

B. NEMERTINEA (see Fig. 15).
(Such as Linews of the sea- shore.)
Generally very elongate, unsegmented,

FIGURE 4. more or less flattened worms, capable
A “Bladder - worm,” Cysticerevs of oreat extension and contraction.
tenuicollis, enlarged about 12 : 5 ' :
diameters. This is the larval Sometimes several yards in length
Teworas of ees and te when extended. Possessing a remark-

found in the lining of the body- able protrusible proboscis, in a sheath
eavities of Sheep, Cattle, etc.

[CESTODA.] lying above the alimentary canal.
, Mostly marine, rarely on land or ip
fresh water, living under stones, etc. .

C. NEMATODA (see Fig. 5). (Such as Ascaris lumbricoides,
the largest round-worm found in man.

Mostly parasitic worms of elongated form, with flexible but not
extensible cylindrical, unsegmented body. (There are many free-
living Nematodes, but these are mostly very minute, living in

6

water or in the soil; some are also para-
sites of plants.) Tail of male nearly always
curved downwards, and proyided either
with a membranous expansion, or with
curved horny spicules, or both.

D. NEMATOMORPHA (Gordiacea)
(see Fig. 13). Extremely long, thin,
wiry-looking worms, traditionally compared
to ‘animated horse-hairs.” Parasitic at
first in the body-cavity of Insects; after-
wards emerging from them to lead a free
life, usually in fresh water.

EK. ACAN-
THOCEKPHALA
(Hchinorhynchus,
etc.—See Fig. 6).
Unsegmented,
cylindrical
worms, more or
less resembling
Nematodes, but
having a_ pyro-
bosecis armed
with many hooks
(see Fig. 7), with
which theyattach
themselves to the
tissues of the
host—usually to

FIGURE 6.
ies : Gigantorhynchus gigas, natural
the lining of the © size,of the Pig. This isa male

Pye ees Z specimen, the female being
stomach or intes- considerably larger. [ACAN-

tines. Larvee in THOCEPHALA. ]
cysts, usually in

aquatic insects or crustacea, sometimes in
fishes, preyed upon by the final host.
Alimentary canal absent.

F. CHAATOPODA. Body divided into
a number of “rings” or
The large Nematode, Segments,each of which
Ascaris megalocephala, 3.4 aces a sea
Fateral/e dine OF the 218. DrOvided syriun certain
intestines of the Horse. groups or rows of
This specimen shows the } istles
curvature of the tail, UFIStLeS.

characteristic of the male (1) OLIGOCHETA
sex of many Nematodes. ah ‘ i
[NEMATODA.] (Karthworms, é&c.).

FIGURE 5.

fi

Chiefly living below the surface of the
soil (often crawling on the surface after
rain, &¢c.), or among rotting timber or
other vegetation. Others, of small size,
in fresh water, or in mud at the bottom
of ponds and streams.

(2) Potycuamra (see Figs. 8, 9 and 16).
Each segment bears generally a fin-like
expansion on each side, from which
bristles project fanwise. These expansions
may be wanting, or confined to the front
end of the body, in forms which inhabit
tubes.

Marive. Some live under stones, or
buried in sand at low-water mark ; many
in tubes of their own construction, at-
tached to _ solid
objects under water.
The tubes are of very
-yarlous appearance,
some being hard
and chalky, others
covered with sand-
grains, bits of shells,

FIGURE 7.

The “head” end of a
typical Echinorhynchus,
greatly magnified, showing
the eylindrical proboscis
covered with hooks.
[ACANTHOCEPHALA. |]

seaweed, &c., others quite transparent.

FIGURE 8.

An example of a
free-living Polychete
worm, Lepidasthenia
elegans, slightly en-
larged, showing the
characteristic paired
appendages. {CH ®-
TOPODA.]

Many of the tube-living worms (see Fig. 9)
have a flower-like crown of feathery “ gills ”’
on the head, which can be protruded from
the opening of the tube.

A few Polychetes lead an entirely free-
swimming life at the surface.

Certain forms, rather unlike the ordinary
conception of a ‘‘ worm,” are included in
this group (Polycheta)—such as the Poly-
noids, some of which are of woodlouse-
like shape and appearance; and Aphrodite
(“ Sea-mouse ”) and its relatives, which
are thick-set animals covered with strong
bristles and beautifully iridescent hairs (see
Fig. 16).

G. GEPHYREA (see Fig. 10). Marine
forms, usually with a simple distended sac-like
body, which shows no external traces of seg-
mentation. Sometimes a crown of short ten-
tacles may be seen expanded at oneend. The
viscera are enclosed in a spacious body-cavity.

8
H. HIRUDINEA. (Leeches.)

Worm-like animals, narrower at the
head end than at the tail, and having
a rounded sucker at each end. Ex-
ternal, temporary parasites mostly
found on vertebrates, sometimes
entering the mouth or nose; living in
water (either fresh or salt) or on land
in moist places, sometimes climbing on
to low bushes, &e.

I. PHORONIDEA (see Fig. 11).
Unsegmented worms living in tubes,
commonly found associated in large
numbers. Tube membranous, some-
times covered with mud and other
foreign
FIGURE 9. substances.

One of the tube-forming Poly-

cheetes, Sabella bombyx, slightly The mouth
enlarged. The specimen has is in the
been removed trom its tube, and

shuws the crown of tentacles. middle of a

[CHATOPODA.] terminal
crown of tentacles, arranged on a more
or less obvious horseshoe-like plan.
Alimentary canal U-shaped, the intestine
running up by the side of the cso-
phagus and opening near the mouth.
The blood is red, with conspicuous.red
corpuscles.

Marine. May be found attached to
solid objects in shallow water, or
inhabiting tunnels bored in calcareous
rocks, shells, &e.

J. ENTEROPNEUSTA (see Fig.
17). Soft-bodied worms which may
have a strong odour of iodoform. The
front end has the form of a conical or
cylindrical ‘proboscis,’ which 1s
followed by a short region termed the
“collar,” encircling the mouth. The
rest of the animal, unsegmented and
often of considerable length, is composed
of several distinct regions, the first of
which is often produced into large
Jateral flaps. A double series of pores FIGURE 10.
occurs on the back or at the sides of Echiurus vulgaris, the “ Spoon-

this * br: shial’’ regi worm,” slightly enlarged.
118 IvVaNneN1a region. (GEPHYREA.]

wv)

Marine; to be looked for on sandy shores at extreme low
tide-mark.

[ Note.—The body is so easily injured that great care is required
to obtain complete specimens ; but they are worth preserving if
the front half can be obtained in good condition. |

FIGURE 1l.

A portion of a crowded colony of Phoronis, seen from above and
slightly enlarged. The tentacles of the individual worms are not
fully expanded. [PHORONIDEA.]

10

OTHER PARASITES WHICH ARE LIABLE TO BE
CONFUSED WITH WORMS.

When searching, by dissection or otherwise, for parasitic
worms, it is not improbable that various other parasites of more or
less worm-like appearance will be found.

The importance of collecting everything of this kind, especially
if there is any question
as to its identity, can-
not be too strongly
emphasised. Hence a
brief reference is made
here to some of the
parasitic creatures
which bear some re-
semblance to worms.

Certain parasitic
Arthropods, in which
the limbs are degraded
or entirely lost, re-
semble worms’ in
general appearance
and are commonly
confused with them.
Among these may be
mentioned the insect
larve or MAGGOTs,
which make their way
into the mouth, nostrils
or stomach, or under
the skin of Mammals,
FIGURE 12. including Man. These

A large Pentastomid, Pentastoma polyzonum, found in ar , o ¥
the Puff-adder ; natural size. [PENTASTOMIDA.] Bre the lary al stages of
certain Khes, and most

of them attack Ungulates—(Horses, Cattle, &c.). Some, like the
‘“‘Warble’”’ flies, raise tumours of considerable size under the skin,
in which the larve live and feed, and from which they eventually
emerge. The so-called “Screw-worm”’ similarly attacks Man.
In other cases, like the Gastrophilus of the Horse, the eggs
swallowed by the animal hatch in its stomach, and the larve
thereupon attach themselves as true internal parasites to the
stomach-wall. They are true maggots and have the usual shape
of such creatures, tapering in front and broadened behind, and
armed with various rings of spines encircling the body.

11

The Pentastomipa (Pentastoma or Linguatula, &c.) are curious
worm-like creatures (see Fig. 12), of doubtful affinities, usually
considered to belong to the Arachnid group, 7.e. to be allied to
Spiders and Mites. But in general appearance they resemble
worms, having a comparatively soft elongated body, without limbs,
and the head being armed with two pairs of sharp, horny hooks.
In their immature stages they may occur enclosed in cysts among
the tissues of almost any part of the body, and in almost any
Mammal or Bird, or living free in its various cavities, more
especially the general body-cavity. The adult forms usually occur
in Snakes or other carnivorous Reptiles, and mostly take up a
position in the lungs of their host.

Parasitic CrusTAcEA of various sorts may also occur. They
are found mostly on Fishes and Whales, or on other Crustacea,
on Mollusca and other aquatic invertebrates; they may assume a
very different appearance from a typical Crustacean. The body
may be reduced to a mere soft sac, without appendages, or with
only vestiges of them. Sometimes there is a pair of elongated
bags of eggs attached to the body, and looking almost like a pair
of legs, or like a pair of long strings. These parasites are very
commonly found, for example, clinging to the gills of Fishes.

Any of the above-mentioned creatures may be safely treated
by ordinary methods of killing, such as corrosive sublimate, and
preserved in alcohol.

Insect-larvee may be killed by immersion for a few seconds only
in boiling water, and then placed in weak spirit, in which they are
to remain till hardened (two or three weeks). They can finally be
transferred to stronger spirit.

HABITAT OF WORMS.

The following is intended as a rough indication of what may
be looked for in a particular kind of locality, though it is impossible
to give a complete guide :—

(i) Inland localities.

(a) Parasitic worms.—Any kind of mammal, bird, reptile,
amphibian, or fresh water fish may be found to harbour
parasites of many kinds. NrmaropEes, TREMATODES,
CESTODES, and ACANTHOCEPHALA occur in all these
groups of animals, either in their larval or adult stages.
As a rule, dissection is the only method of obtaining
them, a special search being made in the alimentary
canal. But some of the TREmMATopEs attach themselves
to the skin of Fishes. LEECHES are sometimes found
adhering to animals (e.g. Frogs) which have recently been
in or near water. Reptiles, especially Snakes, are some-
times found to harbour Pentastoma (or Porocephalus, see

12

Fig. 12), a wormlike creature of doubtful affinities, which
usually takes up a position in the lungs of its host.

Molluses frequently contain the immature stages of
TREMATODES.

Insects, such as beetles, grasshoppers and flies, often
harbour the immature stages of ‘“‘ Harr-worms ”’ (Gordius
and a Nematode worm of somewhat similar appearance,
Mermis). These live coiled up in the body-cavity of the
host. It is to be desired that the adult stages of these
worms should be obtained, and if possible some knowledge
acquired as to their eggs and larvee, and the mode of
infection of new hosts by the larve. It is recommended,
therefore, that when these worms are seen emerging from
insects, or found crawling about, an attempt should be
made to keep them alive for a time in damp earth, water,
etc., in the hope of learning more of their life-history, as
the mature stage is usually only reached after leaving the
insect host. Some small Nemaropss are also parasitic
in insects, but usually require the microscope for their
detection.

(b) Fresh-water worms.

TURBELLARIA are commonly found in any standing
water, crawling on water-weeds or on the bottom, or even
upside down on the surface-film. Since many of them
are carnivorous, and have a liking for decaying matter,
they may sometimes be conveniently caught by sinking a
pot of dead earthworms in a pond or ditch, drawing it up
after a day or two and collecting the Planarians that have
been attracted by it.

Fresh-water fishes,* amphibians, etc., as mentioned
above, should be examined for parasites. Some of the
Insects and Crustacea also harbour NematopEs and
NEMATOMORPHA.

NEMERTINEA are rare in fresh water, but may be
found occasionally.

Many Nematopa occur in fresh water, in the mud at
the bottom, or among plants, but these are chiefly of
microscopic size.

NematomorpHa habitually pass their adult stage of
existence in fresh water, sometimes in standing water,
sometimes in quite rapid streams. They may often be

* Fishes frequently harbour parasitic Crustacea, especially on their gills.
These parasites should, if possible, be preserved, with a note of the position in
which they were found, and information about the ‘‘ host.”

13

found tangled together (see Fig. 13) in great numbers,
and twisted round weeds, ete., on which their eggs are laid.

The fresh-water CHa#ropops are practically all
OuigocH#TA, chiefly small forms living in the mud
round the roots of aquatic plants, or plants growing near
the edge of the water. Samples of mud scraped up from
the bottom of any pond, ditch or stream may contain
many of these worms. PotycHmTA are exceptionally
found in fresh water, and these are most likely to be
obtained by dredging in large

lakes. In brackish water, on
the other hand, PoLtycHaTES
are numerous, living in the
mud, under stones, ete., as do
those of the sea-shore.
LercuHesare often abundant
in ponds, ditches and streams,
where they swim with an un-
dulating movement, or attach
themselves to solid objects, and
walk like “looper” caterpillars.

(c) Land forms.
A number of PLANARIANS (see
Fig. 14) crawl about in moist
places, or may be found among
wet vegetation, such as mosses,
or under stones and decaying
logs. Some of them suggest
slugs, othersare more elongated,
but they are to be recognised by
their extremely soft and slimy
bodies, having no tough skin
like molluses or other worms.

FIGURE 13. Land Planarians are chiefly,
A tangled mass of Gordius aquaticus, but not exclusively, tropical.

natural size. [NEMATOMORPBA. }
NEMERTINES are rare on

land, but one or two have been recorded. They are
likely to be found in wet places, under stones, «ce.

NemMATopDEs of minute size are abundant in soil and
among roots of grasses and other plants. Some are
parasitic on plants, and form various kinds of galls and
other diseased growths on grasses, &c. Mermis, as already
mentioned, is at first parasitic in Insects, but after
emergence from them is often found crawling about on the
soil or on plants, sometimes in large numbers, especially
after rain. It resembles Gordiws in its very wiry
appearance.

14

Gorpius and its relatives are also sometimes found
crawling on the ground, among dead leaves, &c., especially

—

[EERE

FIGURE l4.
A land Planarian, Geoplana
fryi, natural size. [TURBEL-
LARIA. J

in wet forest districts.

OxicocHm®Ta (Harthworms and
their allies) are abundant every-
where in damp soil, under stones,
or among rotting vegetation, some-
times even in the accumulated
water and vegetable débris in
hollows in the branches of trees.
Many species are very small and
inconspicuous. ‘The earthworms
may be obtained by digging, but
many of them emerge from, their
burrows after rain, and may then
be collected, while some species
habitually lie with part of their
bodies out of their holes at night,
except in frosty weather or bright
moonlight. They may be caught
with forceps when found in this
position, but are very sensitive to
light and vibration, and dart back
into their burrows with astonishing
speed if disturbed.

Land-leeches occur chiefly in
the tropics, lying in wait for their
vertebrate prey, either on the
ground or on forest undergrowth,
always provided that the situation
is moist. They often attack man
and domestic animals passing
through such places.

(ii) Marine localities.*
(a) Parasites. As on land and in

fresh water, all kinds of mammals,
birds, reptiles, and fishes may be
examined for PLATYHELMINTHES,
NemaropA, ACANTHOCEPHALA, and
HirupINnEA (see Synopsis). The
last-named are not always attached
to their hosts (usually fishes),. but
may be found free in the water, or
on stones and weeds.

*Much valuable information about the collection and preservation of
Marine organisms will be found in a most useful book, ‘‘ Science of the Sea,”
issued by the Challenger Society. London: John Murray. 6s.

(0)

15

It is also worth while to examine the gills and body-
cavities of crustacea (crabs, &c.), for larval NemaropEs
and TREMATODES, and the various cavities of shell-fish
for larval TremMatopEs, and their empty shells for
NEMERTINES, &c.

Free-living forms in the water
or on shore.

PLANARIANS and NEMER-
TINES (see Fig. 15) are
numerous, being generally
found under stones between
tide-marks or dredged in
shallow water. The NemEr-
TINES are often in tangled
masses. Hmpty shells should
be examined for them, and also
sea-weeds. Some Nemertines &
make gelatinous tubes, or even
burrows in the mud. Pelagic
Nemertines, swimming freely
at the surface, are very rare.

Free-living NEMATODES are
known in the sea, but many
more no doubt remain to be
discovered.

A single NrmatomorrH,
Nectonema, has sometimes been
caught by the tow-net swim-
ming at the surface.

PotycHmTa (see Figs. 8, 9,
and 16, and p. 7) are very
abundant. Unless dredging
operations can be carried out,
they are best obtained by shore-
collecting at low tide. The
burrowing kinds often betray
their presence by leaving es
“casts”? of sand which has FIGURE Li.
passed through the alimentary Nemertine, Hunemertes gracilis,
canal on the surface of the ily twisted position. [NEMER-
ground, and may be obtained Cian!
by digging in such spots.

GEPHYREA (see Fig. 10) will, as a rule, only be
obtained by dredging, but a few may be found between
tide-marks, burying themselves in mud, or forming tubes,
or tubular excavations in soft rock. Some live as ‘‘ com-
mensals ” with corals or sea-urchins, or in empty shells.

16

OLIGOCHETA are rare on the shore, but a few forms
have been found among seaweed above high-water mark,
and some small species are partly marine.

For LrencHes, cf. i (a), p. 14.

For PHORONIDEA, see p. 8.

IJNTEROPNEUSTA (see Fig. 17) may be looked for
on sandy shores at extreme low-tide mark. They

FIGURE 16.
Hermione hystrix, one of the spiny
Polychetes. reluted to the “sea-
mouse”; slightly enlarged. [CH#-
TOPODA. |

form large sand-casts, resembling those of Polychetes,
and they may be found by digging in the neighbourhood:
of these casts. They must be handled with great care

(see p. 9).

LIST OF USEFUL CHEMICAL REAGENTS.

Acetic ACID, GLACIAL (see “ Herries Sublimate’”’). Only a
very small quantity of this will be required. Its use is to
counteract the shrinkage of tissues, caused by solutions containing
corrosive sublimate. A few drops added to the solutions are
sufficient

Anconon. The best is “pure spirit,’ which can often be
obtained more easily abroad than in England, where the heavy
duty makes its price almost prohibitive. For
export only it may be obtained from English
firms at about 2s, 6d. per gallon, or 10s. for a
10-gallon drum (retur nable). The strength of
the spirit as purchased should be about 90 per
cent. For most purposes a strength of 70
per cent. is sufficient for use; this is obtained
by adding 70 volumes of the 90 per cent.
spirit to 20 volumes of water. Similarly, a
50 per cent. solution is obtained by diluting
50 volumes of 90 per cent. spit with 40
volumes of water

Ordinary “‘ methylated” spirit can be used
for some animals, but cannot be diluted, as a
white precipitate is formed on addition of
water. For delicate marine animals it is
quite useless. What is known as Industrial
methylated spirit is, however, suitable for
preserving specimens. In. England it can
only be obtained by special permit from the
Customs authorities, and only in considerable
quantities.

Sudden changes in the strength of this
reagent should be avoided. Thus if it be
desired to transfer specimens from corrosive
sublimate to alcohol, they should be placed,
after washing with water, in a weak solution
of alcohol before being transferred to stronger
spirit.

Cutorat Hyprarr (Crystals), used for ee es
narecotizing certain kinds of worms (e.4. auisseeg ape eatl
Nemertines) before killing them, so as to diameters. [ENTERO-
cause them to die expanded. A few of the .
crystals may be added to the sea-water, or the animals may be
placed in a 1 per cent. solution of the substance made up in sea

water. Further remarks about narcotizing are made on page 21.

18

Corrosive SuBpuimate (HgCl,). A saturated solution of this
exceedingly poisonous substance in fresh water (or sea-water for
marine animals) is a very useful killing and preserving fluid. Its
action is extremely rapid, and is made even more so by heating.
The solution is best made by putting more of the crystals in a
vessel of water than will dissolve; but as solution takes place
slowly the mixture should be made some hours before it is likely
to be wanted. As the solution is used more water can be added
at intervals. So long as some of the crystals remain undissolved
the solution will remain “saturated.” For delicate specimens
which are not calcareous it is useful to add a few drops of glacial
acetic acid to the solution. Steel instruments should not be
brought into contact with solutions of corrosive sublimate.

Objects hardened with corrosive sublimate should be soaked
for some hours in, water or, better, in iodised alcohol (alcohol
70 per cent. 100 parts; tincture of iodine 2°5 parts) before being
placed in alcohol for keeping. Otherwise the sublimate may
crystallise out in the tissues, and spoil the specimens, when
subsequently mounted for the microscope.

N.B.—The saturated solution of sublimate looks exactly like
plain water, and the bottle containing it should be labelled
‘“« Poison.”

FormMAuiIn. The commercial formalin as bought is a solution
of the gaseous compound formaldehyde in water. Its strength is
about 40 per cent. For use it may be diluted with several times
its bulk of water; hence it is very convenient for certain purposes,
owing to its portability. It is also much cheaper than spirit. The
strength most convenient for preserving animals is a 10 per cent.
solution of formalin (or, which is the same thing, a 4 per cent.
solution of formaldehyde). This is made by diluting one volume
of commercial formalin with 9 volumes of water. After haying
been preserved in this solution specimens may be kept in a
weaker one—say 5 per cent. (5 parts commercial formalin to
95 of water).

Note.—As formalin does not give good results with many kinds
of animals, some caution must be used in employing it. It
is advisable not to preserve all the specimens of a kind in
it, but to keep some in alcohol. Further, formalin contains a
certain amount of acid, which is injurious to animals with
calcareous structures, such as worms with calcareous tubes, or
jaws in which the hardening matter is calcareous. Hence
Polycheetes should generally be preserved in alcohol rather than
in formalin. For marine animals the formalin may be diluted
with sea-water instead of with fresh water—an advantage which
this reagent has over alcohol. N.B.—Formalin should not be
used for preserving Nematodes, as it is liable to cause the
specimens to burst.

ae

GLYCcERINE. This may be used, with special precautions, to
preserve the natural colour of an animal. But as this reagent
produces strong shrinkage in the tissues, it is essential to transfer
the specimen into it gradually. This can be done by using
successively stronger solutions of glycerine. The specimen may
first be placed in a 10 per cent. solution of formalin containing a smal/
quantity of glycerine. After a suitable interval (perhaps half an
hour) the specimen, now hardened by the formalin, may be placed
in a stronger solution of glycerine in water; and this process
must be repeated each time with an increasing strength of
glycerine. If the colour is not too fugitive, the specimen may be
hardened in alcohol for a short time, transferred to a dilute
solution of glycerine in alcohol, and then left in an open dish for
the glycerine to concentrate itself by evaporation. In a hot, dry
climate a formalin solution of glycerine might be allowed to
concentrate itself in the same way.

Whatever method is adopted, the specimen should be brought
into glycerine of full strength before the colour is lost.

TopINE, TINCTURE OF. A small quantity of this will be useful
(see “ Corrosive Sublimate ”’).

Soptum CHLORIDE (common salt). A weak solution of this
substance should always be kept ready to hand for the preliminary
washing of parasitic worms. 1 gramme of salt dissolved in 99
cubic centimetres of water will give the required strength (or about
1 oz. in 5 pints).

APPARATUS.

A few dissecting instruments will be required by those who
intend to look for parasites. They need not be many or costly,
but the following would be indispensable :—

Forceps.—Two or three pairs of various sizes, including one

large and strong pair, and one with slender points.

Scissors.—A large strong pair for cutting open animals (some-

times better than a knife). One or two pairs of smaller
dissecting scissors.

Scalpels.—Three or four of different sizes and shapes.

Needles.—A few of different sizes mounted in wooden handles.

Camel's hair brushes.—One or two.

Glass vessels.—Specimen tubes, with corks, of various sizes,

will be required, and can be obtained cheaply from dealers
in natural history requisites.

20

For larger specimens any kind of wide-mouthed bottles
with sound corks or stoppers will do, but perhaps the best
are those with screwed-on metal lids and rubber rings.

Tins, closed by soldering, may be used for specimens in spirit.
They should under no circumstances be employed for
specimens in formalin, which corrodes the metal.

Glass ptpettes—Fitted with rubber caps, are useful for
picking up and transferring small specimens. ‘“ Dipping
tubes,” or straight pieces of glass tubing, with their cut
edges rounded by placing for a few seconds in a flame, are
useful for similar purposes, especially for capturing small
creatures contained in deep vessels of water. (The method
of using a dipping tube is as follows: close one end with a
finger, and bring the other end down into the water until
close to the specimen. Then remove the finger, when
water will rush up the tube, carrying the specimen with it.
Replace the finger over the upper end of the tube, and
withdraw the tube from the vessel.)

Test-tubes.—A few of these will be useful in cleaning speci-
mens, as described below.

Dishes.—Shallow glass or porcelain dishes may be used for
containing the fluids in which specimens are to be killed or
washed, but an ordinary saucer, plate, or other such vessel
will serve most purposes equally well. Hnamelled iron
vessels are particularly useful when travelling—e.g. for
heating the alcohol with which Nematodes are to be
preserved. For this purpose they need only be wide
enough to allow the specimens to be straightened out,
and should not be too shallow, in order to lessen the
possibility of the spirit being set on fire.

SPECIAL METHODS FOR THE TREATMENT
OF SPECIMENS.

CLEANING, Having collected the specimens, the first thing to
do is to clean them from foreign matter, which may be difficult to
remove after they have been killed.

All parasitic worms may be washed by shaking in the 1 per
cent. salt solution. Nematodes and Trematodes can be shaken up
vigorously in a test-tube without damage, but care must be taken
with Tapeworms, which are very fragile. In some cases, such as
Cheetopods, a soft camel’s hair brush may be used to remove
particles of sand, ete., which cling to their bodies, especially if they

21

are very bristly. Water alone may be used for the washing if
salt solution cannot be had, but specimens, especially Nematodes,
must not be left long in it.

Kinurne. After washing, the specimens must be killed with
some reagent which leaves them in a suitable condition for
subsequent examination—7.e. which “fixes” their tissues in a
condition as nearly as possible approaching that of life.

The+ most generally useful reagent is Corrosive Sublimate
(see list of reagents). The effect is more instantaneous if the
solution be heated, and the animals then plunged into it; but it
may also very well be used cold. . An hour or two in this solution
will be long enough for the largest specimens; for smaller ones a
few minutes will suffice. For necessary treatment after corrosive
sublimate, see this heading in the list of reagents.

Formalin (10 per cent. solution) is also good for most
parasites, except for Nematodes, but it cannot be recommended
for the majority of marine worms; specimens left in this reagent
for 24 hours can then be transferred to the weaker solution, or to
alcohol.

For killing parasitic worms, see also other methods given below.

Narcotizine. As it is desirable to get the animals to die in an
expanded condition, it is useful in some cases to anzsthetize them
before killing. This is especially the case with Nemertines, and
worms which live in tubes. They may be placed for from
6 to 12 hours in a solution of chloral hydrate in sea water
(1 per cent.), or a few of the crystals may be simply added to the
sea water in which they lie. When fully extended and showing
no sign of sensation, they may be preserved with formalin or
alcohol. Cocaine may be used with advantage instead of chloral
hydrate.

Another method is to place the worms in a shallow dish of sea
water, and gently pour about ,, part of strong alcohol on the
surface. This will slowly mix with the water and anesthetize
the animals gradually. They can then be transferred to alcohol
to harden, and preserved in it.

Some of the free-living Polycheta must be treated in this way,
or they will break themselves into a number of little pieces when a
killing reagent is added.

Note.—In tropical countries narcotizing is sometimes found
difficult, owing to the fact that decomposition sets -in before the
aneesthetic has had time to take effect. In such cases the alcohol
method will be found to give better results than chloral hydrate.

22

SpeciAL Metuops For Parasitic Worms.
Nematodes.

After washing thoroughly as above directed,* kill by plunging
each separately into a quantity of hot 70 per cent. alcohol. A
temperature of 50°-60° C. is high enough.

N.B.—Care must be used, as the vapour given off is highly
inflammable.) The advantage of this method is that the worms
should die in a straight position.

After being killed in this way the worms are to be stored in
fresh 70% alcohol (never in formalin).

Trematodes.

After the first shaking up in salt solution the dirty liquid is
poured off, and a small quantity of fresh salt solution introduced.
The worms are shaken vigorously in this, and an equal quantity
of saturated solution of corrosive sublimate added quickly, the
shaking being then continued for several minutes. This should
kill and fix the worms in an extended position. They may be left
in the fluid for several days, or transferred at once to water, in
which, in any case, they should be washed for about twelve hours.
After this they may be stored in 70% alcohol as usual.

[Formalin may be used instead of corrosive sublimate, in a
solution of 10% strength, followed by a weaker solution (about 3%) -
as a storing fluid. ]

Cestodes.

Wash gently in salt solution ;f then fix in a solution containing
equal parts of saturated corrosive sublimate and 70% alcohol, to
which add a few drops of glacial acetic acid—the whole heated
to about 50°C. The Tapeworms should remain in the fixing
fluid till it is cold; they are then washed gently in running
water for twelve hours, and stored in 70% alcohol.

PACKING OF SPECIMENS.

The separate small bottles containing worms should be filled
as full as possible with the preserving fluid (alcohol or formalin),
and damage to the specimens by shaking prevented as far as
possible by a light packing of cotton-wool or tissue-paper. Care
mau, “however, be taken to insert the wool in such a way that the

* In the case of Nematodes with a mouth-capsule, a thorough shaking-up
is necessary to remove parts of the tissues of the host, or other débris, from it.

+ When the Tape-worms are long and tend to become much tangled they
should be washed in a shallow dish, and picked out one by one on a splinter
of wood (not a metal instrument) and transferred to the fixing fluid.

23

small specimens cannot get entangled init. The liquid must on
no account be allowed to dry up. When they are to be forwarded
all the small bottles should be placed in a large, wide-mouthed
bottle with a good sound cork or a glass stopper, or better still,
a screwed-on lid with rubber ring. In this the small bottles
should be packed lightly with wool, horse-hair, or soft paper
screwed up into loose balls, and the whole filled up with
the fluid. It is a good plan, if the large bottle or jar is well
stoppered and protected against breakage, to leave the small
bottles without corks, simply plugging their necks with a pellet of
cotton-wool or a stopper of pith—e.g. elder-pith—and then stand
them upside-down in the large jar. There is then much less risk
of the fluid in the small bottles getting dried up, so long as there
is plenty in the big jar. Air-bubbles in the small bottles should
be avoided as far as possible.

N.B.—Small bottles packed in this way, immersed in fluid,
must have their labels imside, and not gummed on the outside.

These ‘“ Instructions” have been drawn up by Mr. H. A.
Baylis, Assistant, Department of Zoology.

Srpney F. Harmer,
Keeper of Zoology.

Br:tisH Musrum (NaturAL History),
CROMWELL Roap,
Lonpon, 8.W.
February, 1915.

LONDON : PRINTED BY WILLIAM CLOWES AND SONS, LIMITED,
DUKE STREET, STAMFORD STREET, S.E., AND GREAT WINDMILL STREET, W.