206 Proceedings of the Biological Society of Washington. 



and (2) ' Hystrixchrysuros 'Lin Gme\. '=Myoxus chry^urus Zimm. There- 

 fore Loncheres, when founded, was virtually monotypic, with Loncheres 

 chrysurus (Zimm.) type by monotypy. 



In my paper published in 1899 (I. c.) all the details of the two cases of 

 Echimys and Loncheres were fully presented, and interested readers are 

 referred to that paper for their fuller history. 



— J. A. Allen. 



THE TYPE SPECIES OF RATTUS. 



In a late paper,* Mr. Oldfield Thomas calls attention to my recent 

 statementt that Mus decumanus {=Rattu8 norvegicua) is the type species 

 of Rdttus Fischer, 1803, J and decides that the type of that genus is Mua 

 rattus. The question is just now one of more than usual importance. In 

 view of the standard set for murine genera by Mr. Thomas in recent work 

 on African mammals, it is highly desirable that the type species of Rattus 

 be determined beyond doubt, for the Norway and black rats represent 

 groups as much entitled to generic rank as many sections of murine 

 genera recently given distinctive names. "Whatever the final decision on 

 the case, the proposal of Mr. Thomas seems to be far from satisfactory. 



The most simple way out obviously would be to accept Rattus from its 

 original publication alone, the type species to be Mus decumanus by 

 monotypy. As Mr. Thomas, in another connection, has recently put it: § 

 " We have not to deal with what Cuvier [in this case Fischer] meant to 

 do, but with what he did do," and he certainly published the Latin name 

 Rattus as a new generic name and mentioned by name only one species, 

 Mus decumanus. The case in that respect is very different from that of 

 Rattus Donovan, 1827,11 because Donovan actually mentioned Mus rattus 

 in his description of the new species of the "rat tribe" Rattus donovani, IT 

 while Fischer lists the single species decumanus in exactly the way we 

 nowadays mention a representative or type species. 



Mr. Thomas argues that [although only a single species, Mus decuma- 

 nus, is included by name in the genus by Fischer] the " genus is dis- 

 tinctly made for the ' Ratte,' French 'Rat,'=il/us rattus, the mention 

 of Mus decumanus being merely as ' the most remarkable of the other 

 species.' " This translation of Fischer is in itself misleading. What 

 Fischer, who was describing the mammal gallery in the Paris 

 museum, really says is: "Die merkwiirdigste unter andern Gattungen 

 dieses Geschlechts ist die Wanderratte (rat surmulot; Mus decumanus)" 

 — that is, among the difierent species of this genus [on exhibition] the 

 most remarkable is Mus decumanus. The case of Troglodytes, in orni- 

 thology, is in some respects similar to the case of Rattus. Vieillot, in 

 describing some American wrens, proposed the new generic name Trog- 



* Ann. and Mag. Nat. Hist., Ser. 8. Vol. 18, p. 240. August, 1916. 

 t Proc. Biol. Soc. Washington, Vol. 29, p. 126. June 6, 1916. 

 X Nationalmuseum der Naturgesehichte zu Paris, Vol. 2, p. 128. 1803. 

 $ Proc. Biol. Soc. Washington, Vol. 28, p. 181. November 29. 1915. 

 II See Hollister, Proc. Biol. Soc. Washington, Vol. 29. p. 126. 1916. 

 IT Nat. Repos., Vol. 3, text to pi. 73, 1834 [1827]. 



