Tuesday, July 27, 2010

Slit Pupils and Intorsion/Extorsion

Yesterday's post about slit pupils and rotating eyeballs generated a lot of fascinating comments and links.



I spent the day yesterday beside a lily pond doing watercolor portraits of green frogs, who obliged me by posing very still——until a bug came along. Their attacks were lightning fast and very athletic. Speaking of slit pupils, frogs have them too!

In case you missed them, here are some of the links relating to these subjects:

Function of slit pupils. (Thanks, Kat!)

Rotation of eyeball in humans (intorsion and extorsion) (Thanks, Nick!)

Fun facts about gecko eyes
and Wiki diagram of eye muscles. (Thanks, Don!)
Yesterday's post about goat eyeballs (with comments afterward).

8 comments:

The Surfin' Squid said...

I like the frogs' names. Quite fitting.

Kat said...

All of James' watercolors are so delightful. Truly this is the best blog on the web.

dzart said...

Those frogs have a lot of character, haha!

Markus Bühler said...

There are a lot of EXTREMELY strange forms of eyes and also pupils among animals. Look for example at the bizarre eyes of cuttlefish, it looks if their pupils would be U-, S- or even nearly W-shaped. Actually this are not really the puils, because this shape is a result of external skin-folds which surround the eye. From personal experience I can also say that sculpting cephalopod eyes can sometimes be really annoying. Those of cuttlefish are comparably easy, but to find good references of squid eyes can be really hard, and it is sometimes really not easy to sculpt them in a realistic way. Another very strange form of "pupil" is those of the nautilus (actualy there are several species of them...), which is a combination of a little hole and a vertical slit. The loricariid catfish from which many species are highly popular among aquarium-owners, have also very bizarre eyes too. They posses a so-called "omega-iris", which enables the pupil to vary from a nearly round to an U-shape:
http://de.wikipedia.org/w/index.php?title=Datei:Loricaria-eye.png&filetimestamp=20050413071816

Claire said...

I was in a staring contest with a cat the other day while it laid on my chest...
The last post really had me paying attention to the contractions and movements within the eyes... Very cool! :)
Not very many animals will let you get really close to their eyeballs and stare directly into them... ;)

perfectingmyperspective said...

I love them! They look wonderful!:)

H.K.Hollinstone studio said...

Very nice watercolours! I haven't painted frogs but I've taken photographs of them in the pond I have. It was mating season and there were at least 14 of them, it was amazing. They are incredible creatures.

Mark Waikien said...

Awesome, Mr Gurney. Appreciate the post! I was actually looking into this specific area, but studying the eyes of squid, which also have slit-like eyes. Nature cooks up some amazing anatomy.