Ivanov, Piotr Pavlovich

(b. St. Petersburg [now Leningrad], Russia, 24 April 1878; d. Kostroma, U.S.S.R., 15 February 1942)

embryology.

Ivanov graduated from St. Petersburg University in 1901 and, from 1903, was an assistant to the professor of invertebrate zoology. In 1906-1907 he traveled through the islands of the Malay Archipelago, where he collected materials on embryonic development of Xiphosura and Scolopendra. In 1909 and 1911 he worked at the zoological station in Naples, studying the embryology and regeneration of annelids. In 1912 at St. Petersburg University he defended his master’s thesis, devoted to regeneration of annelids, and as associate professor gave a course on theoretical embryology. In 1922 Ivanov was appointed head of the embryological laboratory at the university. At the same time he occupied the chair of zoology at the Psychoneurological Institute (later the Second Leningrad Medical Institute), where from 1924 to 1942 he headed first the department of zoology and later the department of general biology, supervising at the same time the work of the embryological laboratory at the All-Union Institute of Experimental Medicine.

In addition to a number of special works Ivanov published two manuals on general and comparative embryology (1937, 1945). The basic morphological generalization that he formulated, comparable in its importance with the theory of germinal layers, was primary heteronomy of the larval body or theory of the primary heteronomy of the bodies of segmented animals . Through his experiments on regeneration of Oligochaeta and Polychaeta, Ivanov established that after the fore end is amputated, only the segments whose structure is characteristic for the larval stage regenerate; during ontogeny the postlarval segments are formed by budding on the hind end of the larval body. The theory of the larval body allows the establishment of the relationship between various types of animals; generalization of the theory is given in Ivanov’s article published posthumostly in 1945.

Ivanov’s theory was used in E. Korschelt’s Vergleichendegleichende Entwicklungsgeschichte der Tiere (2nd ed., Jena, 1936) and in V. N. Beklemishev’s Osnovy sravnitelnoy anatomii bezpozuonochnykh (“Principles of Comparative Anatomy of Inverterbrates”, 1944, 1952);it has been further developed in the research conducted by P. G. Svetlov.

BIBLIOGRAPHY

I. Original Works. Ivanov’ writings include “Die Regeneration von Rumpf- und Kopfsegmenten bei Lum-briculs variegatus Gr”., in Zeitschrift für wissenschaftliche Zoologie, 75 , no. 3 (1903), 327-390; “Die Regeneration der Segmente bei Polichaeten”, ibid., 85 , no. 1 (1907), 1-47; “Die Regeneration des vorderedn und des hinteren Körperendes bei Spirographis spallanzanii Viv.,” ibid., 91, no.4 (1908), 511-588; Regenerativnye protsessy u mnogoshchetinkovyky chervey i otnoshenie ikh k ontogenezu i morfologii annelid (“Regenerative Processes in Oligochaete Annelids and Their Relation to Ontogeny and Morphology of Annelids”; St. Petersburg, 1912), his master’s thesis;“Die Entwicklung der larvalsegmente bei den Anneliden”, in Zeitschrift für Morphologie und ökologie der Tiere,10 , no. 1 (1928), 62-161; “Die Embryonale Entwicklung von Limulus mollucanus,” in Zoologische Jahrbücher, Morph. Abt., 56 , no. 2 (1933), 163-348; Obshchaya i sravnitelnaya embriologia (“General and Comparative Embrology” Moscow, 1937); Embrionalnoe razvitie skolopendry u suyazi s embriobgiey imorfohgiey Tracheata (“Embryonic Development of Scolopendre in Connection With Embryology and Morphology of Tracheata”), in Izvestiya Akademii mauk SSSR, otdel biologicheskikh nauk, no.2 (1940), pp. 831-860; Rukovodstvo po obshchey i sraunitelnoy embriologii; (“Manual of General Comparative Embryology” Mosocow, 1945); and “Pervichnaya i vtorichnaya metameria tela” “Primary and Secondary Metamerism of the Body”), in Zhurnal obshchei biologii,5 no.2 (1945), 61—94.

II. Secondary Literature. See P. G. Svetlov, “Zhizn i tvorchestvo P. P. Ivanova” ( “The Life and Work of P. P. Ivanov”, in Trudy Instituta istorii estestvoznaniya i tekhniki. Akademiya nauk SSSR, 24 (1958), 151-176; and L. N. Zhinkin,” Piotr Pavlovich Ivanova “in Uchenye zapiski Leningradskogo ordena Lenina gosudarstuennogo universiteta im A. A. Zhbanova. Seria biologicheskish nauk, no. 20 (1949), pp. 5—17.

L. J. Blacher