More on the Microscopes of The Challenger Expedition

The Challenger Natural History Workroom

Several other microscopes are illustrated here.  I am curious about the stereomicroscope at the right.  It would not be possible to view (in this configuration) living specimens in water.  I think that's an aquatic microscope further along the same side of the bench, a simple magnifier.  These are incredibly effective: Darwin used one extensively.

A List of Microscopes of the Challenger 

From the Science Museum, London

(I do not see the aquatic microscope (stand for magnifier, I think, with accomodation for trans-illumination.   )

• 1921-678 - Microscope, E. Hartnack and Company; Carl Zeiss Optische Werkstaette, 1860-1872, donated by J Murray
• 1921-679 - Binocular microscope, Smith, Beck & Beck; Ross, Andrew; R. & J. Beck, 1857-69, donated by J Murray
• 1921-679/1 - Binocular Microscope, no. 4351, with triangular adjustable stand by Smith, Beck & Beck, London, England, 1857-1864. Fitted with 1 1/2-inch objective lens by Ross
• 1921-679/2 - Box with accessory eyepieces for binocular microscope by Smith, Beck & Beck, London, England, 1857-1869.  Used on "Challenger" Expedition
• 1921-680 - Petrological microscope used in Challenger research, Voigt and Hochgesang 1860-76
• 1921-680/1 - Petrological Microscope used in Challenger research, Voigt and Hochgesang 1860-76

Another interesting engraving

Microscopic study of slides of Millepora platyphylla

Here are a few slides

RETRACTION: Millepora dichotoma is stable.

A familiar species.  I suspect that Millepora platyphylla, which I studied more extensively, and M. dichotoma partition their reproductive timing.  I observed this species to be in reproductive condition later in the summer, approaching fall.  M platyphylla's first event on Guam was in April,  or late March.

I will use this blog to write more about Millepora spp.

http://www.iucnredlist.org/details/133553/0

[So is M platyphylla on the red list, as "Least Concern" and stable.  I should look before I leap]

The puzzling issue of lunar syncronicity (or NOT!)

In 1985 and 1986, I observed striking synchronous liberation of medusae by Millepora platyphylla colonies on Guam.  During both years, these events happened in early April (though I must recheck the dates).  In about 2003 or 4 (will check dates later) I also saw signs of ripeness at about this same time of year, though I don't recall whether we had data about medusae.

Two other groups of researchers working in Taiwan and Reunion have studied timing of liberation of medusae in Millepora spp.   No "obvious lunar cycle" was observed by Soong et al.

Synchronized release of medusae from three species of hydrozoan fire corals

K. Soong1 and L. C. Cho1

(1) 

Institute of Marine Biology, National Sun Yat-sen University, Kaohsiung, 804, Taiwan, ROC, TW

Abstract   The release of medusae from three hydrozoan fire corals, Millepora dichotoma, M. murrayi and M. platyphylla, was investigated at three sites in southern Taiwan from February 1994 to July 1995. All three species were gonochoristic, and developed and released several batches of medusae between April and May. The duration of open ampulla appearing on the surface of coralla was short, about three months, and could be used to infer the reproductive season of the fire corals between April and May. No obvious lunar cycles of medusa release were found in these species (emphasis mine). Medusa release started before dark at approximately 17:00 h and continued for several hours. Males began releasing medusae earlier than females. Synchronization of medusa release between colonies, i.e., the probability of occurring on the same nights, was significantly higher within a species than between different species. Hybridization in nature among the three species is, therefore, unlikely due to segregation in the spawning dates. Moreover, the synchronization within each species was often significantly higher within versus between sites. The free-swimming medusae released gametes within approximately one hour, and the spent medusae lived for a few more hours. Medusae may facilitate fertilization rates as a result of an apparently negatively geotactic swimming response that results in medusa aggregation at the surface. No differences in the sizes of medusae, eggs and sperm were detected among the three species; however, some characteristic differences of medusa nematocysts were found.

This deserves greater attention.  My primary result seemed to be that liberation of medusae was synchronous.   Soong et all pooled the species of Millepora, it appears.  Regarding synchronization between species and within species, M. dichotoma released medusae much later in the summer on Guam in 1996.

Moseley's Microscope

On August 8, 2007, I posted about Moseley's microscope.  This month, good fortune has indeed shown upon this project.   Professor Steve Ruzin, at UC Berkeley has provided an unparalleled opportunity to observe a Hartnack microscope with a No. 4 Objective and a Number 4 Eyepiece.  

The question foremost in my mind was <how did Henry N. Moseley visualize the anatomical morphology of Millepora as well as he did?>  Here is a digital snapshot of a diatom test slide taken through the Hartnack by Professor Ruzin, using my Canon SD 1100IX point-and-shoot digital camera:

Another image was taken at a higher resolution:

Pretty good, eh?

Summertime (housekeeping)

A personal note. It's summer. A good friend tells of his three reasons for choosing teaching as a profession: Chtistms break, Spring break, and Summer vacation. It's summer again, with more time to spend to catch up on Millepora. This blog is about to be deconstructed and perhaps reconstructed---I haven't decided yet. I'm not sure a blog is the appropriate format for the purpose of THIS project. Even this post is out of place. I have thought about the wiki concept. Maybe something new, or something more traditional. Maybe a regular oldjavascript:void(0) web page. Speaking of which here are two ongoing www items of mine:

• Tank Beach Page
  
• Tank Beach Blog
  

My planned trip to Florida has been cancelled. So perhaps I can use the time to work on this project.

MIllepora day

Either yesterday or today is the day I expect Millepora platyphylla to release medusae here on Saipan.