Sunday, June 18, 2017

Tubercles and tube feet


Yesterday I took a few close-up photos of a Purple Sea Urchin test (or skeleton).


You can see the rounded and raised tubercles to which the urchin spines are attached:


Also noticeable are the podial pores, or the holes from which the tube feet emerge.  

Note that the pores are paired (two are placed side-by-side).  One tube foot emerges from each pair of pores:



To provide some context for these anatomical features of the skeleton, here are two images of live urchins (an adult and a juvenile), highlighting the urchin spines and the extensible tube feet:




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