152 University of California Publications in Zoology [Vol. 20 



was first made by Moquin-Tandon (1860, p. 398) who called Davaine's 

 larger form (his var. A) C. davainei, and the smaller one (his var. B) 

 C. obliqua (p. 399). Accepting page sequence in Moquin-Tandon 

 (1860) as establishing the priority of C. davainei as the first withdrawn 

 species, var. B becomes residual and retains the name liominis, while 

 C. obliqua Moquin-Tandon becomes a synonym of C. hominis. Davaine 's 

 sequence (of vars. A and B) cannot be used to establish the priority of 

 the subsequent reviser's (Moquin-Tandon) names. It follows from 

 the evidence here presented that the correct name for the human 

 intestinal flagellate which Davaine called Cercomonas hominis var. A 

 is Chilomastix davainei (Moquin-Tandon). 



There remains one obscure feature of this problem, namely the 

 question of priority between Davaine's (1860) "Traite des Ento- 

 zoaires" and Moquin-Tandon 's (1860) "Elements de Zoologie Medi- 

 cale. " Both bear the same date, were printed at the same press and 

 were issued by the same prominent publishing house, J. B. Bailliere 

 et Fils, publishers for the Imperial Academy of Medicine in Paris. 

 The English translation of Moquin-Tandon 's work by R. T. Hulme 

 apeared in London in the following year. The date of the preface in 

 Moquin-Tandon 's smaller book is September 1, 1859, and the flagellates 

 are treated in the closing pages. The date of the preface of Davaine 's 

 larger book is September 30, 1859, but the flagellates are treated in 

 the first pages of the book in a "Synopsis" paginated separately in 

 Roman numbers. 



The Bibliotheque Nationale of Paris in reply to an inquiry writes 

 that "L'ouvrage de Moquin-Tandon Elements de zoologie medicale 

 est date de 1859 et figure au journal de la libraire (Depot legal) du 

 24 Septembre, 1859, sous le No. 8501. Le Traite des Entozoaires de 

 Davaine figure du meme journal du 3 Decembre, 1859, sous le No. 

 10774. Sauf retard I'editeur a effectuer le depot, il est dont un peu 

 posterieur. ' ' 



These dates evidently refer to registi-ation merely, rather than to 

 actual deposit of the volumes following publication, since the publisher 

 dated them both 1860. 



There is fortunately decisive internal textual evidence that Moquin- 

 Tandon had before his eyes Davaine's figures when he wrote his 

 descriptions of Cercomonas davainei and C. obliqua. We reproduce 

 both Davaine 's and Moquin-Tandon 's descriptions herewith : 



From Davaine's (1854) original article in which no specific names 

 and no figures are given we quote : 



