Identification Key

   This website is designed to help identify some common settling organisms during their juvenile stage.

   Guide to photographs:
Each photograph is labeled with
-  Day- The day on which the individual was first observed is Day 1, the second day is Day 2, etc.
-  Specimen name- Each individual was given a name.  The name includes the number assigned to the petri dish upon which the individual settled, and a letter corresponding to how many individuals had already been observed on that dish. 
-  Scientific name- Each individual was taxonomically identified to genus and species when possible. 
-  Scale bar- The length of the bar represents the printed numeric value in millimeters.


Transparent body parts that look and feel gelatinous
Two or more nozzle-shaped siphons, sucking in or expelling water
(Older juveniles)  Movement of internal cilia
    Botrylloides violaceus          Distaplia occidentalis            Botryllus schlosseri               Corella inflata


A lophophore (feeding organ):
compressed, comb-like striations inside of the body when retracted
thin, fibrous, and flower-like tendrils extruded from a hole in the body when extended

              Alcyonidium sp.                                Bowerbankia sp.                          Schizoporella japonica


Textured, gritty appearance
May have visible oscula- circular pores
May have spicules- transparent, needle-like spines that look like thin shards of broken glass

         Halichondria bowerbankia                        Haliclona sp. A

Polychaete Worms

Characteristics of spirorbin worms:
Spiral, calcareous shell
Eyes and modified setae (appendages) that extend from the mouth of the shell

             Spirorbin worms


Oval, dome-shaped shell
Distinct, back and forth movement of the organism inside
Slit-like opening (aperture) running down the middle of the shell

              Balanus crenatus


Long branches with tentacled polyps (hydranths) at the ends
Polyps may be enclosed in a clear, glassy encasing (hydrotheca)
May grow stolons (hydrorhiza) that attach the polyps to the substrate
A clear, gelatinous covering (perisarc) over the polyps and the stolons

             Mitrocoma cellularia                                  Obelia sp.