Phylum Annelida (and lophophorates) lab notes

PHYLA BRYOZOA, BRACHIOPODA, AND ANNELIDA

Phylum Bryozoa

Class Gymnolaemata
FEATURES
 Marine bryozoans
 Zooids (individual animals that make up the colony) are tubular with calcified cystid
walls that are fused with adjacent zooids
 Eversion of the horseshoe-shaped lophophore depends on muscle contractions
 Zooids are morphologically distinct individuals (pore plates allow exchange of coelomic
fluid)


Bugula sp.
IDENTIFY
 Lophophore
 Colony shape
 Sheath
 Zooecia
 Zooid
 Avicularium (if present)



Class Phylactolaemata
FEATURES
 Freshwater bryozoans
 Cylindrical zooid possesses a horseshoe-shaped lophophore
 Zooids do NOT possess a calcified exoskeleton, and the coelom is continuous
between individuals.
 Do not possess distinct individuals (clones).
 Zooids never specialized for defense; all the modules are functionally equivalent
 Eversion of the lophophore is brought about by muscles that deform the body wall
(i.e., they do not attach directly to the lophophore itself).


Pectinatella sp.
IDENTIFY
 Lophophore (some may be retracted)
 Mouth
 Intestine
 Statoblast (asexual buds formed in summer/fall)
 Zooid colonies that project from one side of a soft colonial sac
Phylum Brachiopoda

, FEATURES
 Include lamp shells
 All marine
 Appear similar to molluscs but are oriented dorso-ventrally and the ventral valve is
(usually) larger than the dorsal valve.



Class Inarticulata
FEATURES
 Two valve shells are held together by muscles and other tissues
 Shell teeth are absent
 No hinge
 Calcium phosphate shell
 Complete gut

Lingula sp. (Shell intact)
IDENTIFY
 Pedicle
 Dorsal valve
 Ventral valve



Class Articulata
FEATURES
 Two valves are articulated by means of teeth (ventral) and sockets (dorsal)
 Calcium carbonate shell
 Shell opened and closed by the direct action of specialized muscles
 Blind gut tract
 No anus

Terebratella sp.
IDENTIFY
 Lophophore tentacles
 Mouth
 Gonads
 Mantle




Phylum Annelida