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Darwin Correspondence Project

From V. O. Kovalevsky   28 February [1870]1

Dear Sir!

Your letter adressed to Heidelberg was delivered there to my wife and so I received it some days ago at Munich.2 As You are kind enough to take an interest in our doings I schall give You some details of our common plans. My brother3 book now a leave from Russia for 18 months and is now in the position of a boy before the long vacation not knowing how to make the best of it; he intended to go to Naples or Cherso4 to finish the developement of the Bonelia commenced two years ago, but not finished as it was not the season of developement. The thing is very interesting (if his conclusion about the supposed males is correct), as it present us with such a complete dimorphism, the male and female at first glance seeming to belong to diferrent groups or even classes of worms. As it may interest You, and the little notice of it is printed in Russian I send You the Plate and some explanation.5 You certainly know the very interesting paper of Lacase Dudier in the Annales des Sciences Natur. on the Bonelia and the splendid figures given there,6 Lacase had in hands about a hundred Bonelias, but always females; Smarda who also wrote an article about these Sipunculidae7 could never detect a male, so was it the first time with my brother; he found at a lucky place a whole colony of Bonelias, but all were females and after mutilating hundreds he gave it away in despair; but returning to the same place in September 68 and beginning a new massacre he saw in the outer bag or infundibulum of the sexual organ of the animal (female) in every specimen some strange planarias, very small, from 2 to 7 in every female. They were covered with cilia and seemed quite like Small Turbellarias with a white patch or line in the centre, this white line contained spermatazoa. As at this special period literarly every female had these planarias living in her sexual organs there is great probability that they are the males. If the case will stand future investigation it will certainly be one of the best instance of dimorphism, the female being a Sipunculus and the male a Planarian like animal; so as I said his intention was to go to Naples, but as it seems he changed his mind and intends to go to a new place where no naturalist worked before, the little bay is called Thor and lays on the Sinai peninsula not very far from Suez, facing rich coral reefs. I, for my part am against his undetaking the journey before October, as in the summer the pilgrims going from Africa to Mekka generally bring with them pest, cholera and what not.—8

My wife wished to go to Berlin, and the Rector the know physiologist Dubois Reymond9 was one of our advocates, and a better one is difficult to have, but the matematicians were against it, holding to the strict sense of the law. Generally the matematicians are the worst thing living, not only in Germany but also in our country and I hope in England. One of the principal opponents to the admission of ladies was Kunt,10 a true pure, who at one of the Natural Science Congress proposed a toast “for the theory of numbers (Zahlenteorie) as a part of mathematics that till the present was not besmeared with practical application”. So are they all, more or less. But happily Kirchhow took a great interest in her and promised to give her a special investigation about light in the summer, so she remains a suer at Heidelberg.11 For my part I am quite incertain what to do, going to Vienna and working with the assistance of Tehermak and Suess,12 or going to England and working alone whithout direction. I think I’ll take the latter course; firstly because with Your kindness to me I will have as good assistance as can be; scondly because I will have the use of the best collections existing.—

The one point which most interest me is, can I have trough a member the use of the Library of the Geological Society, not only reading there, but taking the books out to my lodging as my principal workink time is in the night. I think I shall take the liberty to write about this point to Mr. Huxley, as the free use of the Library is one of the Chief point which determine my going to London.—13 The vacation commences this Sunday, and Monday I hope to break off and go to Nizza with my wife and one of her friends, a young lady about her age but “learned in the law”, as she is pursuing now law studies at Heidelberg.14 What will Your ladies say of such an ultra blue stocking.

The principal attraction of the coast of Nizza for me is the rich fauna of mollusks, the splendid series of deposits from the trias to the upper Chalk and especially the wonderful new Wealden, only not of the Jurrasic but of the Upper Cretaceous period with a developement of 600 feet of freschwater sediments and lignites, at least so is it affirmed by Coquand and I am very restless to see the wonder with my own eyes and especially to collect and study its fauna.15 In case You write me, please to adress Nizza, poste restante. With Your permission I write You from Nizza.— My compliments to Mrs. Darwin and the ladies

Yours very truly | W. Kowalevsky

Munich | 28 February


1. Grown up female of Bonelia always sticking with her pyriform and in an aperture of a rock (Lacase— Ann. des Sc. Nat. vol X.)

2. Bonelia cut from the dorsal side g. ova in the Leibeshöhle, q. anal aperture; m. uterus; p. inpundibulum trough which the ova pass from the F cavity of the thorax into the uterus   v bag where the planarias live

3. Supposed male magnified 70 diam; rs receptaculum seminis t. infundibulum; h. granular mass clothing the cavity, from which undeveloped spermatozoa are cast of; s. glomercili of spermatozoans swimming freely in the cavity

4. Infundibulum of the receptae. sem. (magnified 500 diam). with flimmerzellen



The year is established by the reference to Sofia Vasilyevna Kovalevskaya’s being in Heidelburg; she was there between May 1869 and mid-1870 (Koblitz 1983, pp. 88, 97).
Letter to V. O. Kovalevsky, 22 February [1870]. Kovalevsky’s wife was Sofia Kovalevskaya.
Cherso: now Cres, in Croatia.
See enclosure. Bonelia is an incorrect subsequent spelling of Bonellia, a genus of spoon worms.
Kovalevsky refers to Félix Joseph Henri de Lacaze-Duthiers and Lacaze-Duthiers 1858. The article had four plates, showing the general morphology, and the digestive, reproductive, and nervous systems of the animal.
Bonellia is now in the family Bonelliidae in the phylum Echiura. The family Sipunculidae is now placed in the phylum Sipuncula (peanut worms). Kovalevsky refers to Ludwig Karl Schmarda’s description of Bonellia viridis (Schmarda 1852).
Tor, on the south-west coast of the Suez Peninsula, served as a quarantine station for pilgrims returning from Mecca (Columbia gazetteer of the world).
Emil Heinrich Du Bois-Reymond.
Kovalevsky refers to August Kundt.
Gustav Robert Kirchhoff was a professor at Heidelberg (DSB).
Gustav Tschermak and Edward Suess.
Nizza: Nice. Kovalevsky also refers to Anna Mikhailovna Evrainova.
Kovalevsky refers to Henri Coquand.


Columbia gazetteer of the world: The Columbia gazetteer of the world. Edited by Saul B. Cohen. 3 vols. New York: Columbia University Press. 1998.

DSB: Dictionary of scientific biography. Edited by Charles Coulston Gillispie and Frederic L. Holmes. 18 vols. including index and supplements. New York: Charles Scribner’s Sons. 1970–90.

Koblitz, Ann Hibner. 1983. A convergence of lives: Sofia Kovalevskaia, scientist, writer, revolutionary. Boston: Birkhäuser.

Lacaze-Duthiers, Félix Joseph Henri. 1858. Recherches sur la bonellie (Bonellia viridis). Annales des Sciences Naturelles. Zoologie 4th ser. 10: 49–110.

ODNB: Oxford dictionary of national biography: from the earliest times to the year 2000. (Revised edition.) Edited by H. C. G. Matthew and Brian Harrison. 60 vols. and index. Oxford: Oxford University Press. 2004.

Schmarda, Ludwig Karl. 1852. Zur Naturgeschichte der Adria. I: Bonellia viridis. Denkschriften der kaiserlichen Akademie der Wissenschaften. Mathematisch-naturwissenschaftliche Klasse (1852) part 2: 117–40.


Describes his brother Alexander’s discovery of male of Bonellia, a striking example of dimorphism. Encloses a plate with notes on his brother’s work.

The difficulty his wife, Sofya Kovalevsky, has had as a woman in being admitted to Berlin University. Kirchow [Gustav Robert Kirchhoff], at Heidelberg, has taken an interest in her.

Letter details

Letter no.
Vladimir Onufrievich Kovalevsky (Владимир Онуфриевич Ковалевский)
Charles Robert Darwin
Sent from
Source of text
DAR 169: 61
Physical description
ALS 4pp encl

Please cite as

Darwin Correspondence Project, “Letter no. 7121,” accessed on 27 March 2023,

Also published in The Correspondence of Charles Darwin, vol. 18