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Darwin Correspondence Project

From Alexander Onufrievich Kovalevsky1   25 September 1870

Naples.

25 Septem 70.

Monsieur

Mon frère me fait savoir, que vous desiréz inserer dans l’ouvrage que vous publiez une citation, que mes nouvelles etudes sur le developpement des Ascidres constatent mes premieres assertions que les larves des Ascidres simples sont des animaux vertebrés.2

Les resultats de mes nouvelles rescherches sur le developpement des Ascidres sont maintenant sous presse, dans l’Archiv fur Mikroscopische Anatomie de Max Schultze.3 Dans cet article, je constate, a l’aide d’une serie de nouvelles observations, que les larves des Ascidres sont de vraies vertebrés, que leurs systeme nerveux se forme a laide d’un sillon dorsal qui se ferme dans tube—système nerveux des Ascidres; je constate encore que la chorde dorsale des larves des Acidres se developpe de la même maniere que chez les vertebrés; Je donne des dessins de la coupe transversale de la larve (fig.) qui presente le systeme nerveux (n), la chorde (ch), l’intestin (d) et les cellules musculaires (m)

[DIAG HERE]

J’espère que j’aurais le plaisir de vous faire parvenir un exemplaire de mes nouvelles études sur le developpement des Ascidres dans le courant du moi Novembre ou Decembre.—

Pendant l’anné passé (1869) j’ai étudié l’embryologie des annelides et je trouvé que la chorde dorsale existe chez beaucoup des Annelides.— Peût–être vous vous rapeléz Monsieur, du grande tube nerveux(?)—riesiege Rohren Nervenfasern que Leydig a decrit chez les Lumbricus;4 Claparéde (Zeitschrift fur Wissenschaftliche Zoologie Bd. XIX p. 588, 89–90) a demontrés que cet enorme quasi Nerv se trouve à lexterieur de la Nevrilemme.5 Mes etudes sur l’embryologie de ces tubes m’ont demontré qu’ils se forment de la même maniere que la chorde des vertebrés. Je trouvai chez les embryons des Lumbricidae trois feuilles embryonaire—correspondant aux trois feuilles embryonnaire des vertebrés; du feuille exterieure se forme le systeme nerveux et l’epitehlium exterieur, du feuille interieur (Darmdrüsenblatt)6 l’epithelium du canal instestinal, du feuille mediane les muscles, la nevrileme et les chordes ou “riesiege Röhrenfasern” de Claparède.

Mon Etude sur l’embryologie de Lombric est sous presse dans le Memoires de l’Acad. de St. Petersbourg.7

Mon frère m’ecrit qu’il vous serait agreable si j’etudie l’organisation du mal des cirripèdes (Scalpellum) ainsi que l’histoire du developpement et de formation du mal et de ses organes genitaux en comparaison avec la femelle.8 Je ferais tout mon possible pour ressoudre ces ?? d’autant plus que je rencontrait un fait pareile chez des autre forme, chez la Bonelia viridis.9 Pressisement, je trouvé, que le mal de Bonelia est une petite Planaire, ou mieux Turbellaire, d’un millimetre.10 Les males se trouvent dans l’uterus de la femelle, on trouve dans chaque Bonelia femelle 4 ou 5 males— Dans l’organisation du male on trouve plusieur cas de ressemblanse avec la femelle; l’organisation des organe genitaux du male et de la femelle se ressemble beaucoup.11 Il est bien possible que dans la Bonelia nous trouverons un exemple, que seulement un sexe (femelle) changeat graduellement sa forme primitive, tendit que l’autre sexe (le mal) resta dans sa forme primitive de Turbellaire. J’espère de pouvoir étudier le developpement de la Bonelia, cela devra resoudre la question.

Je resterais a Naples encore toute une anné et je serais extrément heureux si je pourais vous être utile ou en vous envoyant quelque forme de la faune du golfe de Naples, ou en faisant quelques études dont les resultats vous interesserais exclusivement

En vous envoyant cette lettre, Monsieur, je profite de l’ocasion pour exprimér tout mon devouement aux idées dont vous avez enrichit la science et de vous priéer d’agréer ma salutation le plus distingué | Prof. A Kowalevsky

Footnotes

For a translation of this letter, see Correspondence vol. 18, Appendix I.
Alexander’s brother was Vladimir Onufrievich Kovalevsky. See the letter from V. O. Kovalevsky, 5 September [1870] and n. 4.
Kovalevsky refers to A. O. Kovalevsky 1871 and to Max Johann Sigismund Schultze. In Descent 1: 205, CD referred to Kovalevsky’s earlier paper on the embryology of ascidians (A. O. Kovalevsky 1866b) and to the fact that Kovalevsky had done further research on the subject, but did not cite the later article. No copy of A. O. Kovalevsky 1871 has been found in the Darwin Archive.
‘Riesiege Rohren Nervenfasern’: giant tube of nerve fibres (German; a reference to the median giant fibre). Franz von Leydig described this organ in Lumbricus in Leydig 1864, pp. 154–5.
The reference is to Edouard Claparède and Claparède 1869. Claparède noted the similarity between the nerve sheath of the earthworm and the myelin sheath of vertebrates (Claparède 1869, p. 590).
‘Darmdrüsenblatt’: gut-gland-layer (German; a reference to the endoderm).
Kovalevsky refers to his paper on the embryology of worms and arthropods (A. O. Kovalevsky 1869). It appeared in the 1871 volume of Mémoires de l’Académie Impériale des Sciences de St.-Pétersbourg.
CD’s letter to Vladimir Onufrievich Kovalevsky has not been found, but see the letter from V. O. Kovalevsky, 20 September 1870.
Bonelia viridis is an incorrect subsequent spelling of Bonellia viridis, the green spoonworm.
Bonellia viridis is no longer placed within the family Planariidae of the class Turbellaria. It is in a separate phylum, Echiura.
Bonellia viridis is sexually undifferentiated in larval stages, and differentiation is determined by environmental factors alone. For more on the development of sexes in this species, see Berec et al. 2005.

Translation

From Alexander Onufrievich Kovalevsky1   25 September 1870

Naples.

25 Septem 70.

Dear Sir

My brother has let me know that you want to insert a citation in the work you are publishing, to the effect that my new studies on the development of the Ascidians confirm my earlier assertions that the larvae of simple Ascidians are vertebrate animals.2

The results of my new research on the development of the Ascidians are now in press, in Max Schultze’s Archiv fur Mikroscopische Anatomie.3 In this article, I confirm, with the help of a series of new observations, that the larvae of the Ascidians are true vertebrates, and that their nervous system forms by means of a dorsal sulcus which closes into a tube—the nervous system of the Ascidians; I also confirm that the dorsal chord of the larvae of the Ascidians develops in the same way as in the vertebrates; I give drawings of the transverse section of the larva (fig.) which shows the nervous system (n), the chord (ch), the intestine (d) and the muscle cells (m)

[DIAG HERE]

I hope that I shall have the pleasure of sending you a copy of my new studies on Ascidian development in the course of the month of November or December.—

In the last year (1869) I have studied annelid embryology and I have found that the dorsal chord exists in many Annelids.— Perhaps you recall, Sir, the great nerve tube(?)—riesiege Rohren Nervenfasern that Leydig describes in Lumbricus;4 Claparéde (Zeitschrift fur Wissenschaftliche Zoologie Bd. XIX p. 588, 89–90) has demonstrated that this enormous quasi Nerve is found outside the Neurilemma.5 My studies on the embryology of these tubes have shown me that they form in the same way as the vertebrate chord. I found three embryonic layers in Lumbricidae embryos—corresponding to the three embryonic layers in vertebrates; the nervous system and the exterior epithelium form from the external layer, the epithelium of the intestinal canal from the internal layer (Darmdrüsenblatt),6 the muscles, the neurilemma and the chords or “riesiege Röhrenfasern” of Claparède from the median layer.

My study on Earthworm embryology is in press in the Memoirs of the Acad. of St. Petersburg.7

My brother writes that it would please you if I studied the organisation of the male in cirripedes (Scalpellum) as well as the history of the development and formation of the male and of his genital organs compared with the female.8 I would do everything I could to resolve these ??, the more so because I have encountered a comparable fact in another form, Bonelia viridis.9 Namely, I find that the male of Bonelia is a small Planarian, or rather Turbellarian, a millimetre long.10 The males are found in the female’s uterus, and in each Bonelia female one finds 4 or 5 males— In the male’s organisation one finds several cases of resemblance with the female; the organisation of the genital organs of the male and female is very similar.11 It is indeed possible that in Bonelia we find an example in which just one sex (female) gradually changed its primitive form, whilst the other sex (the male) remained in its primitive form, the Turbellarian. I hope to be able to study the development of Bonelia, that ought to resolve the question.

I will remain at Naples for another whole year and I should be most happy if I could be of service to you either by sending you some form of fauna from the gulf of Naples, or by carrying out some studies whose results would be of interest exclusively to you

In sending you this letter, dear Sir, I shall take the opportunity to express all my attachment to the ideas with which you have enriched science and to offer you my most distinguished greetings | Prof. A Kowalevsky

Footnotes

For a transcription of this letter in its original French, see p. QQQQ.
Alexander’s brother was Vladimir Onufrievich Kovalevsky. See the letter from V. O. Kovalevsky, 5 September [1870] and n. 4.
Kovalevsky refers to A. O. Kovalevsky 1871 and to Max Johann Sigismund Schultze. In Descent 1: 205, CD referred to Kovalevsky’s earlier paper on the embryology of ascidians (A. O. Kovalevsky 1866b) and to the fact that Kovalevsky had done further research on the subject, but did not cite the later article. No copy of A. O. Kovalevsky 1871 has been found in the Darwin Archive.
‘Riesiege Rohren Nervenfasern’: giant tube of nerve fibres (German; a reference to the median giant fibre). Franz von Leydig described this organ in Lumbricus in Leydig 1864, pp. 154–5.
The reference is to Edouard Claparède and Claparède 1869. Claparède noted the similarity between the nerve sheath of the earthworm and the myelin sheath of vertebrates (Claparède 1869, p. 590).
‘Darmdrüsenblatt’: gut-gland-layer (German; a reference to the endoderm).
Kovalevsky refers to his paper on the embryology of worms and arthropods (A. O. Kovalevsky 1869). It appeared in the 1871 volume of Mémoires de l’Académie Impériale des Sciences de St.-Pétersbourg.
CD’s letter to Vladimir Onufrievich Kovalevsky has not been found, but see the letter from V. O. Kovalevsky, 20 September 1870.
Bonelia viridis is an incorrect subsequent spelling of Bonellia viridis, the green spoonworm.
Bonellia viridis is no longer placed within the family Planariidae of the class Turbellaria. It is in a separate phylum, Echiura.
Bonellia viridis is sexually undifferentiated in larval stages, and differentiation is determined by environmental factors alone. For more on the development of sexes in this species, see Berec et al. 2005.

Summary

Outlines the evidence for his view that ascidian larvae are true vertebrates presented in his paper ["Weitere Studien über die Entwicklung der einfachen Ascidien", Arch. Mikrosk. Anat. 7 (1871): 101–302]. CD can cite this as confirmation of AOK’s earlier claims.

Letter details

Letter no.
DCP-LETT-7326
From
Alexander Onufrievich Kovalevsky
To
Charles Robert Darwin
Sent from
Naples
Source of text
DAR 169: 52
Physical description
4pp (French)

Please cite as

Darwin Correspondence Project, “Letter no. 7326,” accessed on 25 March 2019, http://www.darwinproject.ac.uk/DCP-LETT-7326

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

letter