Here is some of the results from the work I was doing in the lab last week. I'll start with some images from my further microscopy adventures. This is a preserved specimen of Raja erinacea
("little skate") that fits in the palm of your hand. Though considering the number of chemicals it has been in, I wouldn't recommend you try that.
Next is a close-up I'm pretty proud of. This is a dorsal (top) view of the skate's eye and some of the spines surrounding it. This is about the limit of my improvised camera-microscope skills.
And here is the right side of the jaw, with the lower jaw in focus. Can see how they're related to sharks, eh? =)
This is a close-up on the supports for the pectoral fins (the "wings" of skates and rays). There's a lot of variability between one support and the next-- keep in mind that this is cartilage, not bone. The stain is a different kind than the one used on the Zebrasoma flavescens
I posted a while ago.
And for the last microscope photo, this is a really interesting picture. Skates alone have developed heavily modified pelvic fins that closely resemble a vertebrate foot. They use this appendage (called a crux, plural crura) to "punt" themselves along the bottom. One of the professors at my school is doing studies on this method of locomotion, and you can see one of his papers (with better pictures) here: http://www.bioone.org/bioone/?reques...e=03&page=0553
I opened up some of the membranes in this fin to make the cartilage a little easier to see, which is why it looks ragged. Normally all of the supports are interconnected.
And here's an update on the live embryo I've been observing for the past few months. I've included previous pictures so you can get a sense of its development. I think someone lied to me about the age of the embryo, so I'm still trying to find out what it is. In a flow-through system like ours they can take a year to develop.
February 24th, 2004
March 24th, 2004
April 21st, 2004
And finally, here is a video I took so that I could have a reference to describe "tail beating" behavior. Tail beating allows the embryo to increase water flow (thus oxygenation) when its in its egg case. However, its a heavily encoded behavior, so they'll do it even when they're not in an egg case. Sorry for the poor quality and shortness, but hope you enjoy it: http://members.aol.com/enduringdecay...acea_42104.avi
That's all from me for now. I may post my final report after I turn in the project a week from today. 8O