The “Recherches zoologiques” of the “Mission scientifique au Mexique et dans l’Amérique Centrale” (“Mission” hereafter), were published as “livraisons” (deliveries) over a period of nearly half a century between 1870 and 1916. Henri Milne-Edwards, head of the Laboratoire des Mammifères et Oiseaux, was the editor of the whole publication; after his death, the editorial work was continued by Alphonse Milne-Edwards, his son, and Léon Louis Vaillant. “Recherches zoologiques” were intended to include 7 parts (“parties”): Première partie: “Anthropologie du Mexique”. Deuxième partie: not published. Troisième partie: “Études sur les Reptiles”. Quatrième partie: “Études zoologiques sur les Poissons…”. Cinquième partie: “Études sur Xiphosures et les Crustacés…”. Sixième partie: “Études sur les Insectes Orthoptères and Études sur les Myriapodes”. Septième partie: “Études sur les Mollusques terrestres et fluviatiles”. See ^{Crosnier and Clark (1998)} for more details. The “Recherches zoologiques” were themselves a division of the more comprehensive “Mission” series including: 1 - “Les travaux préparatoires et le suivi des événements” (1864-1877), 2 - “Géologie” (1868-1871), 3 - “Linguistique” (1869-1885), 4 - “Recherches botaniques” (1872-1886), 5 - “Recherches historiques et archéologiques” (1885), 6 - “Recherches zoologiques” (1870-1916). These divisions were comparatively of very unequal importance, at least judging by the number of published pages.

The “Reptiles and Amphibians” (the latter called “Batraciens”), making up the third part, was originally subtitled “Étude sur les Reptiles et Batraciens”, but later was split into 2 sections. Different sections of the third part are variously attributed, according to different published references, to Henri Milne-Edwards (1800-1885), Auguste Henri André ^{Duméril (1812-1870)}, Marie Firmin Bocourt (1819-1904), Paul Brocchi (1838-1898), François Mocquard (1834-1917) and Léon Louis Vaillant (1834-1914), with some authorities even adding Fernand Angel (1881-1950) as author, e.g., ^{Savage (2002}: 39). In this third part Milne-Edwards only authored the “Introduction” to Brocchi's contribution (1882); the name of his son, Alphonse Milne-Edwards, is twice mentioned as author of amphibian plates in the same contribution. Duméril “filius”, head of the Laboratoire des Reptiles et Poissons since 1857, died on 12 November 1870, the very year of the publication of the first pages, and his contribution was limited to the “Introduction” to the whole herpetological part (cf. ^{Milne-Edwards, 1882}: 1), although he doubtless also participated in the original organization of the herpetological sections. By contrast, Firmin Bocourt, who worked at the Museum since 1834 as an assistant of the 2 Dumérils and later of Vaillant, was by far the principal author of the “Reptiles” section, for both text and illustrations. In 1881, following Milne-Edwards’ ruling, Bocourt, at the age of 62 (he was not then dead, as implied by ^{Crosnier and Clark (1998: 95)}, he died on 4 February 1904, at the age of nearly 85), had to give up the “Amphibians” because he was so preoccupied with the “Reptiles”, and forwarded all of his notes and illustrations to ^{Brocchi (1877a},^b, ¹⁸⁸¹: 3) to write the “Batraciens” part. From then on, part 3 was split into 2 sections, and after Bocourt's death the subtitle “Études sur les Reptiles et Batraciens” was changed to “Études sur les Reptiles”. Léon Vaillant was the successor of A. Duméril as the head of the Laboratoire, from 1875 to 1909, although Émile Blanchard held the post on an interim basis from 1870 to 1875, and necessarily he had a role in the long production of the herpetological parts of the “Mission” project. Bocourt, Brocchi, Mocquard, and Angel were under Vaillant's direction, but Vaillant only authored the eight-page “Avant-propos”, which was placed at the beginning of the Reptiles section. Together with Bocourt, Vaillant was the author of the fourth part, “Études zoologiques sur les Poissons…”, of which the last “livraison” was published posthumously (1916). François Mocquard was approximately the same age as Léon Vaillant, but he began to work at the laboratory much later, from 1884, and was promoted to Assistant in 1891; he completed the “Reptiles” section left from the death of Bocourt, and he wrote some 110 pages to complete this section. Finally, the name of Fernand Angel appeared only as the artist for the last six plates of “Reptiles” (1909); he began work at the Museum in 1905.

After it was published, the “Étude sur les Reptiles et Batraciens” got few and rather negative reviews, notably from ^{Gray (1873)}, who was latter vindicated (^{Anonymous, 1874a}), and ^{Cope (1884)}. Subsequently, however, it has been considered an important and even essential taxonomic work for the region (^{Adler, 2007}, ²⁰¹⁴; ^{Flores-Villela, 1993}; ^{Smith & Smith, 1973}), because dozens of new taxa from Mexico, Central America and the West Indies are first named in this book, with fine illustrations and detailed descriptions. In modern times this work has not been easy to access because it is absent from many institutional libraries in Mexico and Central America and because most herpetologists in that part of the world do not read French. However, a facsimile reprint of the entire herpetological section was published in 1978 (Arno Press, New York), and the text (Reptiles only, without illustrations) is currently available on the Internet at https://books.google.fr/books?id=oItuSppLGVAC.

During some work related to the type specimens of species described by Alfredo Dugès and located in the Museo de Historia Natural Alfredo Dugès, of the University of Guanajuato (^{Flores-Villela, Ríos-Muñoz, Magaña-Cota, & Quezadas-Tapia, 2016}), one of us (OFV) encountered a problem with the authorship of one taxon. The difficulty and the confusion to assign a proper author to such a taxon has led us to present the following tables. A first attempt was a table partly adapted from ^{Vaillant (1909a: viii)}, who wrote the “Avant-propos”, as noted above. This table was greatly enhanced thanks to published data and our unpublished data.

In his table, Vaillant did not give details regarding authorship for the different parts of the text or plates, but detailed the splitting of the work into “livraisons”. Much later, ^{Smith and Smith (1973: X)}, based on a personal communication from Edward H. Taylor, published a list of the publication dates and authorship of the different parts, but unfortunately it lacks the relationship between “livraisons, feuilles” (printed leaves of paper) and pages, and has some inaccuracies. More recently, ^{Crosnier and Clark (1998)} wrote a very detailed study of the entire “Mission” publication and its 7 parts including their sections, which is by far the most complete, and with data about authorships and pagination. Crosnier & Clark correctly recognized part 3 as including the “Reptiles” (1998: 88) but later (1998: 95) erroneously gave it the number 2. These authors outlined several editorial blunders and odd changes which appeared during the 46 years of publication. They also minutely analyzed all the volumes of the “Bibliographie de la France”, from 1873 to 1916, noting all data in connection with the “Mission” series of works. In the series “Catalogue général de la Librairie française” the data are both incomplete and sometimes imprecise, see Table 3. The only point to note is that the year of publication suggested for the 10th “livraison”, 1885, disagrees with the date given here, 1886, which is also the date given on the original wrappers. An important notice about the administrative history of the whole “Mission” was recently published by the French “Archives nationales” (^{Le Goff & Prévost-Urkidi, 2009}), but it does not include any detail about the dates of publication; for the “Reptiles”, they only gave the inclusive dates 1870-1909 and for the “Amphibians”, 1882, which is correct only for the second section of this book. As outlined by ^{Crosnier and Clark (1998: 90)}: “… it was particularly regrettable that the “Imprimerie nationale” (or “impériale”, till 1870), which published the various “livraisons”, did not appear to possess any archive relative to the exact dates of publication”.

Actually, the only accurate way to get the most probable dates of publication is to examine copies that still have the original wrappers or covers of the “livraisons”. Crosnier & Clark could only find 2 sets that still have all wrappers, one at the French National Library (“Bibliothèque Nationale”) in Paris, and the other one in the Zoology Library of the Natural History Museum, London. Another one was bought in 1962 in Paris by one of us (KA), who kept all of these wrappers and communicated the dates to Hobart Smith for his book (^{Smith & Smith, 1976}: App-1). Crosnier & Clark also compared dates from wrappers with dates of published accounts, and concluded that because all of them are in accordance, the dates of the wrappers can be considered as reliable. The only disagreement appears with “livraison” 15, where the year (wrapper and Vaillant's table) is given as 1897, but the precise date of registration by the “Bibliographie de la France” is stated as 17 January 1898 (cf. Table 4, note 10).

With this set of data we believe it is important to make available the details of the publication of the “Mission” for the “Reptiles” and “Amphibians”, so that mistakes concerning the authorship and year of publications are not disseminated, creating confusion and nomenclatural problems. Therefore, Table 1 (“Reptiles”) and Table 2 (“Batraciens” = “Amphibians”) detail which of the authors of this work is responsible for the different parts of it. Table 4 provides, when available, precise dates of publication, according to the weekly journal “Bibliographie de la France”, which had the aim to give an exhaustive list of all printed matters as soon as they appeared. These tables may serve as a guide when citing particular “livraisons” in references about the “Mission”, rather than referring to the work in its entire form. Table 5 gives the artists for the plates, most always following their mention at the bottom of individual plates. Despite careful research, it has been impossible to find any biographical data about some of these artists, and even a first name remains missing for 2 of them (see Appendix).