Historical concepts of the medusoid of Millepora spp. and Hickson's follies

Dick Randall, my mentor at the University of Guam Marine Laboratory, alerted me to Sydney Hickson's having mangled the systematics of Millepora spp., in the early days of my study.   Hickson, the ultimate lumper decided to spell it Millepora sp.(1)   He had determined that all of the then-known species of Millepora were eco-variants of a single Atlantic species, Millepora alcicornis.  Hullbrandt Boschma, decades later, restored sanity to the taxonomic picture of the group  but the grand synonymization of Hickson lives on as a footnote in taxonomic history.

This was far from the only blasphemy conducted by Hickson.  I will not treat here his fantastical description of the developmental cell biology of Millepora sp., which, to be fair, he retracted in a succeeding publication.  But in his error of judgement about the structure of the medusoid of Millepora spp. Hickson promulgated a misconception of a different kind: his drawing of the medusoida  portrayed a deformed, post-spawning individual, apparently turned inside-out, possibly dead.  This erroneous image was co-opted at some point as a component of a representation of the structure of Millepora spp., based upon the remarkable line drawing from H. N. Moseley's reports from the Challenger Expedition.   The composite has propagated through almost every textbook of Invertebrate Zoology until recently, illustrating the medusa (or, more properly, medusoid) swimming above the cross section of the colony. 

If Hickson committed an absurdly erroneous lumping the species of Millepora, another chapter in the history of misunderstandings of  the medusoid of Millepora spp. involves an over-zealous splitting. In his tome, a taxonomy of the medusae of the world, Mayer had split the medusae of Millepora spp.---as the Medusae Milleporinae---out from all other hydrozoan medusae, the "veiled medusae,"  on account of its purported absence of a velum (veil).  A question remains: did Hickson originate this misconception as well?   

 I was thrilled when I collected medusae (or medusoids) of Millepora platyphylla in April, 1985, I was able to observe them in a dish, at the University of Guam Marine Laboratory.  Luckily, Professor Lucius Eldredge was on hand, and I asked him to check whether they had a velum; he  verified the presence of a velum.   The medusae I observed had not yet spawned.  It was immediately apparent that they differed substantially from the drawing I had seen, I think from Hickson.  It seemed to me that the configuration of the medusae in Hickson's drawing would be that of a spent individual---one that had already expelled its gametes. 

Mangan or Duerden may have been the last person to report observing medusae of Millepora alcicornis., in 1909 or 1910.  

Hickson wove a fantastical tale based on misinterpretations 

I just re-read Hickson's fantasy analysis of the reproductive biology of Millepora plicata, based on a remarkable degree of mis-interpretation of histology.  He weaves an entirely fantastical tale of the origin of the ovum, it's development, internal fertilization (which does not happen at all), and growth of a larva and it's expulsion.  

My blog post does not treat of this.  It is incredible.  Literally.  I am not suggesting you read it, but cite it here.  In his favor, he was indeed prolific, and he ultimately retracted this story.  But it's not the only issue among Hickson's publications.  Or among the other leading lights of Zoology in the latter part of the 19th Century who failed to critically examine or repeat his work, but built entire new stories upon Hickson's foundation.  

Hickson SJ. VIII. On the sexual cells and the early stages in the development of millepora plicata. Philosophical Transactions of the Royal Society of London.(B.). 1888 Dec 31(179):193-204

  

It is tempting to suggest that Sydney Hickson, one of the most prominent marine zoologists of his day (around the turn of the 19th to the 20th century), as a charlatan.   Indeed, one of my long-languishing projects has been to track down the life of the anomalous drawing of Medusae Milleporinae and prove whether he was the originator of this long-lived false cartoon of the medusa of Millepora spp.  After reading through one of his anatomical studies recently, I have come to appreciate what a remarkable observer he was.  However, he certainly suffered from a massive level of presumption.  

And, in a sense, it's a reflection of the nature of Zoology of that era, that he was so highly respected as a zoological authority that his errors persisted for so long, without being tested.  This reflects badly upon the assumption that science proceeds by the testing of hypotheses.  And re-testing.  Hickson obviously took the massive level of respect he enjoyed to heart.  

In Chuukese, there is a word that applies: baatá.  This verb refers to persons who takes flattery to heart.  An example would be a boy who, having been singled out as a good basketball player, goes out and buys basketball gear, and inhabits the cloak of the praise he has enjoyed.  In Chuuk, this is taken to a remarkable extreme: one can "abaatá" (cause to baatá) another person through disingenuous flattery.  

Hickson is an unfortunate example of someone whose entire body of work is perfused with the fruits of his baatá.  But it is on the greater community that he was placed on such a pedestal. 

Another example is found in a previous post of mine: https://millepora.blogspot.com/2022/10/an-obscure-mention-of-millepora-work-by.html

(1)  spp. designated multiple species; sp. a single species, though it be unnamed.  I will use the correct "spp." herein.

ADDENDA

  As I searched via google (scholar?), an amazing thing happened: I saw my on name

  on a Google citation, from a mailing list thread of many years ago.  

  Remarkably, I had written about Hickson's blunders in a post to a

  microscopy mailing list (which, I need to determine).  

Davis, A. E. (2002). Microscopic Artifacts In The History Of Biology. Microscopy Today, 10(2), 18-21.

I had discussed the issue of Hickson's fantasy development cycle, referring to it as a consequence of microscopic artifacts.  Artifacts have been referred to as   “artificial structure(s) or tissue alteration(s) on a prepared microscopic slide as a result of an extraneous factor.”  

From my query on that mailing list:

(About) Sydney Hickson's early work on Millepora spp. (Cnidaria:Hydrozoa) fire corals. It seems an incredible lapse, a wholly fabricated natural history account, one that persisted for a considerable period in the fabric of the mythology of biological knowledge. I am interested because reproduction of Millepora platyphylla is the subject of incompleted thesis research of mine.

Hickson published a report on reproduction of "Millepora" around the end of the 19th Century. ... In this report, which I do not have available at this time, he included several plates of drawings depicting a putative sequence of reproductive events in this organism. We now understand that his depiction is not even close to the way that Millepora spp. (which were later redesignated as proper individual species through painstaking work by Boschma-notwithstanding the issues recently raised by molecular work) reproduce.  The depiction involved dozens of drawings, and a sequence of events based on a misinterpretation of what are apparently artifacts....

Also,.   

... Hickson's erroneous drawings of the meduse of Millepora lived on for over 3/4 of a century in virtually every Invertebrate Zoology textbook published until the late 1980s or 1990s. His erroneous description of the medusa of Millepora as lacking a velum led to the designation of a separate branch of hydromedusae by Mayer, as the only hydrozoan medusa without a velum. My unpublished observations in the 1980s as well as published observations by John Lewis of McGill University showed that the medusae of Millepora spp. clearly possess a velum. I apologize for monopolizing the bandwidth. I hope this is as fascinating a topic for others as for myself, and not considered off-topic.

  

In 1900 Hickson was able to examine material that included medusoids.  The following is a correction in his paper on the subject,, wherein he reported on these findings.  

Hickson, Sydney John. "The medusae of Millepora." Proceedings of the Royal Society of London 66.424-433 (1900): 3-10. 

Correction.—In a former communication to the Royal Society, 1 described certain cells in the cenosarc of Millepore from Celebes as ova. Since the discovery of the female medusa, I have carefully re-examined my preparations, and satisfied myself that I made a mistake. These cells are not ova, but the cells which ultimately give rise to the large kind of nematocyst.

 

My earliest introduction to Millepora spp.

 Professor Richard Randall had been disallowed from being an MSc thesis advisor by the big shots at the University of Guam Marine Laboratory, I think unfairly.  

Shortly after I had arrived on Guam to begin graduate studies in Early August of 1984,  Dick Randall made himself known to me by stopping to offer me a ride down the hill to the Laboratory, and introducing himself as a coral biologist (he is also a geologist).  Immediately he engaged me in discussion of ideas for a thesis topic. 

I explained that I was interested in reproductive periodicity in Tridacnid clams, particularly in endocrine control of gametogenesis.  Such a study would necessarily involve elucidating the phenology, the seasonality, indeed, every aspect of the timing of reproductive events.  This topic was a huge turn-on for me.   

 

  At that point he introduced me to Millepora spp., the fire corals.  He explained that the Calcium Carbonate hard parts of these corals bore outward evidence of reproductive status---the Ampullae that sheltered the medusae within them.  Thus, it seemed, it would be possible to study the reproductive periodicity by the most expedient of all possible methods: examination of hard parts over time.  

(Professor Lu Eldredge stood in his stead.  It is on me and me alone that I did not complete the thesis that was required to earn an MSc from UJ. of Guam.  Had there been a plan B, I would certainly have the MSc. degree today.  Dick Randall deserved to be treated with more respect, as I might add.

So it was I started collecting fragments of Millepora spp.   At that time, I took every opportunity to snorkel, and each time I did I collected at least one fragment of Millepora spp., usually M. platyphylla.  That first term, I was enrolled in a statistics class; I hoped I would be able to draw some conclusions using some statistical means or another on the timing of reproductive efforts.  I had learned from R. K. Trench at UCSB about Tridacnids.  and the interesting variations in the patterns of timing.  I had hoped to be able to study neurosecretory control of gametogenesis of the giant clams.  This interesting twist regarding the biology of Millepora would provide an opportunity to complete a study on the side, in my spare time, no sweat, while engaged in other pursuits.

Professor Randall kept a large plastic tank of Calcium Hypochlorite out on the lanai behind his lab/office, for cleaning corals.  I gradually built up a number of bleached coral specimens, but had not recognized ampullae.  Perhaps I would be able to find time later on to examine the coral skeletons and create a database.

Dick warned me about the work of Sydney Hickson, a prominent british zoologist of the late 19th Century---one of the big names.  Hickson had made the error of synonymizing all species of the genus Millepora as a single species, M. alcicornis, an Atlantic species found prominently in the Caribbean.  Boschma would, much later, correct the record in  a series of long papers on the specific characters, and revised the systematics of the genus.  

When I first laid eyes on the medusae of Millepora platyphylla, I was on the beach at Toguan Bay, Guam.  it was obvious to me that the illustrations by Hickson of the medusa of Millepora had also promulgated an egregious error; this illustration was widely disseminated, as part of a revised drawing of Moseley in most Invertebrate Textbooks.