Download Annelid lab info

Lumbricus terrestris
- preserved specimens for dissection
External Anatomy:
Prostomium (observe under dissecting microscope for
external sensory organs), peristomium, clitellum, setae
(dissecting microscope), metameres, pygidium (periproct)
Internal Anatomy:
Pharynx, Anterior ganglion (brain), pharynx (is it
jawed?), pseudohearts, esophagus, esophageal glands,
calciferous glands, crop, gizzard, intestine, nephridia,
dorsal and ventral bv
 Associate structures with specific segments!
 What are the functions of these structures and
how do they relate to the animal’s lifestyle?
Male: Seminal receptacles, seminal vesicles, testes
Female: Ovary
Are these animals monecious or diecious?
- model:
Some of the smaller features such as the pseudohearts
and anterior ganglion, nephridia and some of the
reproductive structures are small and as such easier to
find on the model
Lumbricus terrestris
- cs slide (pre and post clitellum)
Body Wall: Cuticle, epidermis, circular muscles,
longitudinal muscles, setae
Excretory: Nephrostome, nephridium bladder and
nephridiopore
Body cavity: Coelom, dorsal bv, ventral bv, nerve cord
(dorsally or ventrally located?), chloragogue cells
(Store nitrogen and neutralize toxins. What is their
equivalence in vertebrates?), , typhlosole (dorsal flap in
intestine, anterior or posterior to clitellum?), digestive
tract (can you tell which part of the digestive tract
you are looking at?) lined with gastrodermis.
 You may need to look at more than ONE slide in
order to find all these different structures!
Nereis virens
- preserved specimens for dissection
Is this an errant or a sedentary polychaete? How can
you tell?
External anatomy: Prostomium, peristomium, prostomial
palps and tentacles, eyes (located on the pro- or
peristomium?), jaws, tentacular cirri, pygidium with
caudal cirri
Appendages: notopodium, neuropodium, dorsal cirrus,
ventral cirrus, setae (Falcigers vs spinigers . What is
the difference? Simple vs compound setae? What is the
difference?), aciculum (acicula)
Internal anatomy: alimentary canal (What is the
difference between Nereis and Lumbricus?), mesenteries,
eggs (if animal is reproductive, will be loose in coelomic
fluid, so make a wet mount of the coelomic fluid), dorsal
and ventral bv
Other Polychaete worms:
Chaetopterus sp. – parchment tube worm
-peristomium extended into a collar, greatly enlarged
notopodia behind the 10th segment (parapodia appear fan
shaped), suckered neuropodia
 refer to textbook etc. information to understand
how the lifestyle of the animal works with its
morphology!
Sabella sp. – fan worms
- crown of tentacles called radioles, parapodia reduced
or absent
 animal lifestyle?
Amphitrite sp. - elongated gills and tentacles, parapodia reduced or
absent
 animal lifestyle?
Aphrodite aculeate
- body covered in a dense mat of setae, received its
name due to its ventral appearance (which is what?)
 animal lifestyle?
Hirudo medicinalis (most popular preserved specimen)
- medicinal leech
- preserved specimens for dissection (may be Hirudo)
External anatomy: Dorsal eyes, (anterior to mouth)
metameres and annuli (subdivisions of the metameres,
not true segments, often obscure the 32-4 true
segments), anterior sucker (central mouth), jaws?
(presence of jaws indicates that you are looking at
Hirudo, posterior sucker, anus, male pore (segment 10,
penis might be everted), female pore (segment 11)
Internal anatomy: (you will have to cut ventrally, how
can you tell dorsal from ventral surface?),buccal cavity
(with jaws?), intestine, gastric caecae, rectum
- slide, to find further internal features and compare to
preserved specimen
proboscis and proboscis cavity, male and female atrium
(how do you distinguish?), ovary, testes, (vas deference),
intestine, gastric caecae, rectum, dorsal anus