Centipede Fangs

[NikonUser]

I made a permanent mount of an exoskeleton, exuvia, of a Stone Centipede which was a mistake in that the various components cannot be rearranged for clearer images.

Top image is a ventral view of the head, and 1st body segment with its legs modified into fangs. A poison gland, p, in the terminal portion has a duct that opens just before the tip of the fang. The enlarged lower part of this modified leg in life encloses a huge muscle which surrounds a cuticular apodeme, a. which terminates with an attachment to the inside base of the fang, aa in lower image. When the muscle contracts the apodeme pulls the fang into they prey; scorpions are predators.

It appears that the joints between the 3 segments at the outer edge of the fang's base are ball-and-socket joints whereas on the inner surface the cuticle simply folds over.

Tech. details: Nikon D600 (after a wet clean of the sensor!) on an Olympus BHS and 2.5x NFK relay lens.
Top image with Olympus 2x S Plan Fluorite (NA 0.08); bottom with Olympus 10x S Plan Apo (NA 0.4).
Until recently I found it impossible to get any decent illumination for the 2x objective with the 'normal' substage condensers. Now I have an Olympus BH2-ULC condenser with an NA of 0.02 and this gives a bright uniform field of view for low power objectives.
Bottom image with selective focus to emphasize the poison gland.
Both are stacks with Zerene PMax.

[Planapo]

I made a permanent mount of an exoskeleton, exuvia, of a Stone Centipede which was a mistake in that the various components cannot be rearranged for clearer images.

I think it worked out very nicely and there are lots of interesting structures to be discovered in this photo, despite the parts in their natural overlapping position.

Do you use xylene (aka xylol) in the last step of water removal for mounts in balsam? I'm asking because I've got hold of an older book on microscopy with "recipes". One for insect exoskeleton preparation for balsam mounts advises to do so, and I wonder if that's still the way it should be done.

I find that when swinging in this 2x SPlan Flourite after I have focused with another objective before, I have to refocus quite a lot. Do you experience the same with yours?

--Betty

[arturoag75]

very clear and crisp brightfield images..the low power condenser make a great job
arturo

[NikonUser]

Arturo, I am very pleased with the condenser; it took a couple of years to find one on ebay. I find the images too bright, the exosketon is a lot darker and the tips of the fangs are heavily sclerotized and almost black.
I had to overexpose to show the poison gland and its duct.

Betty, Both Xylene and Toluene work well but I no longer use either as the fumes bother me - headaches. Also both of these leave specimens extremely brittle.
I now use Isopropyl Alcohol, sold in the local chemist as 99% but it mixes with Canada Balsam so I suspect it has no water in it.
I use it for dehrydration, 10% stages for delicate stuff, and go directly from the 99% into CB.

My technique is to place the dehydrated specimen on a slide in a drop of 99% IPA, add a fresh drop of 99% and then add a drop of CB. I then gently heat the slide for about 20 seconds (holding it over a regular incandescent light bulb works) to drive off excess alcohol. Another drop of CB and a cover glass.

"I find that when swinging in this 2x SPlan Flourite after I have focused with another objective before, I have to refocus quite a lot. Do you experience the same with yours? "
I just checked the focus with the 2x and compared it to the 10x SPlanApo: Focus is spot on, no refocusing needed.

[abpho]

Looks like an x-ray image to me. Awesome!

[Planapo]

NU, Thanks for the details of your recipe with CB which obviously works fine.

And thanks for checking the parfocality of the 2 SPlan FL. As my bulb has gone bust when I switched on the microscope today, I have to wait until new bulbs arrive to recheck mine.

--Betty

[Charles Krebs]

NU,

Which condenser were you using with the 2X prior to getting this low power one?

[NikonUser]

Obviously my comment "'normal' substage condensers" is meaningless. For me 'normal' meant what I had at hand (BH2-CD, -PC, -NC), none of which were designed for low power (2x - 4x) objectives.
I also have a Swift 1.25 condenser with a top lens that screws off exposing a much wider lower lens. This condenser would rest on the substage carriage of the BHS and performed better than my other condensers for the 2x obj. But not using any substage condenser was equally as good (or poor).
I never could find a reasonably priced (again meaningless) BH2-SC, mainly because I was hoping to find a BH2-ULC which turned out to be expensive but worth the price.

[Franz Neidl]

Hello NU,

Until recently I found it impossible to get any decent illumination for the 2x objective with the 'normal' substage condensers. Now I have an Olympus BH2-ULC condenser with an NA of 0.02 and this gives a bright uniform field of view for low power objectives.

Thank you for your interesting words about the low power condenser. I have the same problem with brightfield and the 4x objective. What was your experience with the 4x objective? Exactly the same as with the 2x objective?

Maybe I too I will have a look to bay I used Nikon low power substage condenser for my Nikon Eclipse 600 microscope. It would be a great help to take pictures from bigger plankton organisms.

BTW: Congratulations to your award for the month of December!

Franz

[NikonUser]

Hi Franz,
Yes, I was having similar poor illumination with the 4x objective.
My new ultra-low condenser solved all these problems.

I measured the top lens of the BH2-ULC = 27.5 mm diameter, compared to 11 mm for my other condensers.