What have we here?

[Charles Krebs]

I should probably know this one, but I have a tough time being certain with some of these smaller ciliates. One "culture" I have is loaded with them! The average specimen seems to be about 15x25 microns in size. I've included a second composite image of individuals that show an interesting "mouth" structure, and in one case, three prominent caudal cilia.

The top shot shows them up against a Volvox. I "discovered" that if I oil my phase contrast condenser to the slide, and rotate it to the dark-field position I can get a very nice "circular oblique" lighting with my 100X by carefully closing the aperture built into the objective. I can't believe I have never tried this before today! I really like the way it looks.

The second image shows 4 individuals taken with conventional brightfield (maybe slightly oblique).

Hopefully there's enough here for you eagle-eyes to tell me what the are






100X objective, 2.5X photo-eyepiece. Canon 350D. Electronic flash.

[Ken Ramos]

Browsed through Jahns and came up with what may possibly be Cinetochilum margaritaceum, 15-45um.

Oval body, oblique truncate at rear. Buccal cavity in posterior half of body, with undulating membranes on both sides of mouth cavity. 3-4 long caudal cilia. Family Cinetochilidae.(Jahns, Phylum Ciliophora pg. 243, fig. 435)

Some very excellent and detailed images, as usual Charlie.

[rjlittlefield]

Awesome images, as always!

I am particularly stuck by how beautifully the upper image illustrates the mucilage coat of the Volvox completely excluding the little ciliates.

I had read about that coat previously, but this image leaves a much stronger impression than any I have seen before.

--Rik

[Charles Krebs]

Ken... you might have it! Thanks.
This looks very close:
http://microscope.mbl.edu/scripts/micro ... geID=11953

[Ken Ramos]

Sometimes drawings are more detailed than the actual photographs seen on these sites, with your being an exception Charlie. I have often wondered at some of these websites though. I look at their images and then compare them to those seen here in our forums and we without a doubt have some of the best microphotographers to be found on the web.