Purple urchin

Species: Strongylocentrotus purpuratus

Phylum: Echinodermata

Class: Echinoidea

Order: Echinoida

A large part of this class involves learning how to use different techniques in microscopy to highlight particular larval features that we want to see more clearly. Below are two pictures of the same S. purpuratus larvae under different filter settings. The central pluteus is developing normally, with eight arms, clear epaulettes, and a well-defined rudiment to the left (in the image) of the gut. you can even make out the suckers of the juvenile tube feet on the rudiment! The larva in the upper right corner, on the other hand, is developing abnormally (hence the extra wide body and deformed/absent features).

The vignetting in the images is a result of the photography style--because these filter sets are only found on several of our compound scopes, I had to take these pictures down one of the eye pieces with my phone. 

- Andrew Miller