(b. Besse, Var, France, 8 January 1811; d. Martinique, 7 October 1852)
Souleyet is one of several health officers in the French navy who won renown for zoological work connected with a voyage of circumnavigation. Nothing is known about his family and childhood. His entry into the health service of the navy was fairly late; and after some difficulty at the outset of his career, he obtained in 1835 the opportunity to sail on the voyage of the Bonite around the globe under the command of August Nicholas Vaillant. The main purpose of the voyage was to transport French consular agents to various parts of the world. In conformance with the pratice begun on Louis-Claude de Freycinet’s voyage of the Uranie (1817- 1820), all scientific research was to be handled by members of the navy. Fortuné Eydoux, surgeon major of the expedition,was charged with zoology, and Souleyet, as second surgeon, became associated with his research.souleyet also benefited from the friendship and guidance of Charles Gaudichaud-Beaupré, pharmacist and adjoint to the expedition for research on natural history. Gaudichaud introduced Souleyet to study of pelagic mollusks, which became his field of specialization. The Bonite left Toulon in February 1836, stopped in South America, Hawaii,the Philippines, and various parts of the lndian and Chinese seas, and returned to Brest in November 1837. Because the brevity of the stopovers precluded an investigation of the ecology or anthropology of the areas visited, the naturalists concentrated on collecting new species, particularly microscopic mollusks. The collections were deposited at the Museum of Natural History and cataloged by the professors there.
Eydoux, who after the voyage became physician in chief at Martinique, died there in 1841, leaving Souleyet with most of the work of publishing the zoology of the voyage. Another tour of duty during 1846– 1849 interrupted publication. Souleyet finally returned to Paris in January 1850 and completed the work in 1851. Free to pursue his career,he was preparing for the competitive examination become a professor when he received order embark for the Antilles. Leaving France reluctantly, he reached Martinique in July 1852, during epidemic of yellow fever, and soon fell victim to the disease. The results of Souleyet’s anatomical and physiological investigations of pteropod and gastrc mollusks are contained in the second volume of zoology of the Bonite voyage and in various memoirs. Zoologists had been divided over the composition of the Pteropoda, a group created by Cuvier and the position of this group among the mollusks Souleyet reworked its classification, removing Heteropoda and dividing it into four natural families. Accepting Blainville’s ranging of the Pteropoda among the Gastropoda, Souleyet pointed the analogies between these two groups of molluska. He demonstrated that the alary expansion of the pteropods is merely the foot of the gastropod in disguise. In 1852 Souleyet completed a monograph on the pteropods begun in 1830 by P.-C.-A.-L. Rang. Besides writing the entire text, which appears to be an abbreviated version of the zoology of the Bonite, Souleyet added several plates depicting newly discovered species.
Also important is Souleyet’s description of the nervous collar of mollusks, which he believed to correspond to both the brain and the spinal cord of vertebrates. He argued that the apparently anomalous nervous collar of pteropods was merely a modification of the general form of that structure in mollusks.
From 1844 Souleyet was involved in a controversy with Armand de Quatrefages on the subject of “phlebenterism.” Quatrefages had established a new order of gastropod mollusks, the Phlebenterata. which he defined as degraded gastropods with no proper respiratory organs and an imperfect or absent circulatory system. He claimed that a system of intestinal canals, a “gastro-vascular apparatus,” took over part of the functions of respiration and circulation. Elaborating on the general ideas of his master, Henri Milne-Edwards, Quatrefages believed that the animal kingdom was composed of several series in which the type was effaced at the lower limits. Phlebenterism was a general phenomenon of degeneration among animals.
Souleyet, in a series of memoirs and notes beginning with “Observations sur les mollusques gastéropodes designées sous le nom de Phlébentéréspar M. de Quatrefages” (Comptes rendus ... de l’Académie des sciences,19 , 355–362), attacked Quatrefages’s position. He argued that the Phlebenterata were not essentially different from other Gastropoda, that they did have a complete circulatory system including veins, and that the “gastro-vascular” canals were in reality hepatic canals not without analogues in other mollusks. The controversy touched on the large questions of whether types degraded, whether exterior and interior conformation can be independent, and whether organs can degenerate and he replaced by other organs developed especially for the purpose. The issues were important enough to merit two commission reports, one by the Academy of Sciences and the other by the Society of Biology. The former report was noncommittal, and the latter declared in favor of Souleyet.
I. Original Works. Wih Fortuné Eydoux, Souleyet published Voyage autour du monde exécuéte pendantannées 1836 et 1837 sur la corvette la Bonite commandée par M. Vaillant,Zoologie, 2 vols. plus atlas (Paris, 1841–1852). This work contains Blainville’s instructions to the zoologists of the voyage in the name the Academy of Sciences and his report on the zoological results of the voyage. The instructions and report had previously been published in Comptes rendus...de l’Académie des sciences. 1 (1835), 373–377, and 6 (1838), 445–460, respectively. With P.-C.-A.-L. Rang, Souleyet published Histoire naturelle des mallusques ptéropodes (Paris, 1852). A list of Souleyet’s memoir written alone or in conjunction with Eydoux is in the Royal Society Catalogue of Scientific Papers, V, 760.
II. Secondary Literature. Apparently the only biographical notice on Souleyet is S. Petit, “Louis François-Auguste Souleyet,” in Journal de conchyliologie4 (1853), 107–111. For a helpful review of Souleyet’s second volume of the Bonite voyage, see Pierre Gratiolet, “Zoologie du voyage de la Bonite, par MM. Eydoux et Souleyet,” in Journal de conchyliologie, 4 (1853), 93– 107. On the phlebenterism controversy, see the commission report of the Academy of Sciences, presented by Isidore Geoffroy Saint-Hilaire in Comptes rendus...de l’Academie des sciences,32 (1851), 33–46, and in Mémoires de l’Académie des sciences..., 23 ; (1853), 83–104; and the commission report of the Society of Biology, presented by Charles Robin in comptes rendus des séances de la Société de biologie, 3 (1851) 5–132.
Toby A. Appel