Recent Literature. 
I0 3 
1883]. 
forms. On page 14, in speaking of Sylvia orj> heus and Sylvia jerdoni , 
ij after referring to the points of difference between the two, and the occur- 
rence of intermediate examples, he saj r s : “We must therefore admit that 
the difference between the two forms is only a subspecific one, being com- 
pletely bridged over by examples from intermediate localities.” The two 
forms are then described, and are numbered and stand in the work itself 
1 and in the “systematic index” as species in regular standing, the text 
alone — not the nomenclature or the numeration employed — r- showing that 
they are viewed otherwise. They stand “5. Sylvia or jheus" \ “6. Sylvia 
jerdoni ,” followed by tables of references and detailed descriptions in the 
same manner as species of unquestioned standing. Mr. Sharpe’s method 
of treating subspecies is far more reasonable, they being formally recog- 
nized as such in his nomenclature, by which method the two forms would 
stand as follows : “5. Sylvia orfiheus ;” “subspecies a Sylvia jerdoni" in the 
body of the work and as “5. Sylvia orjheus ” and “a jerdoni ” in the System- 
atic index. To take another example from the many scattered through the 
volume, at page 16 we have, as a subheading “ Sylvia curruca , Sylvia affi- 
nis , and Sylvia althea ,” followed by a paragraph from which we quote the 
following: “This is an excellent example of a species in the process of 
breaking up into three species. ... I prefer to treat them as subspecies, 
adopting the provisional hypothesis that the intermediate forms are the 
result of the interbreeding of the different races.” Each subspecies is then 
(very properly) treated separately, but with the status, to all appearances, 
of accepted species, although in the text they are spoken of respectively 
as the “European form,” the “Siberian form,” and the “Himalayan form” 
of the Lesser Whitethroat. To specify another example, the Rock Thrush 
(p. 316) is said to have “two extreme forms, between which every possible 
intermediate form occurs” ; yet these two forms stand, so far as regards 
nomenclature and numeration, on the same footing as fully admitted 
species. In further illustration of this point we may cite the cases of the 
Turdus “ jallassi" and Turdus “ swainsoni ” groups. The three forms 
composing each appear to him “to be deserving of subspecific rank,” or 
as “ imperfectly segregated species,” but each has nomenclaturally the 
same status in his book as the “fully segregated” species. The Mexican 
and Central American intergrading forms of Turdus , even in some cases 
where Salvin and Godman have united them as one species, are similarly 
treated. This seems to be a “ hard and tight” adhesion to the binomial 
system little to be expected from one who goes so far as to admit and even 
seemingly to advocate a better system. 
Toward the close of the volume, however, are a few instances of a pe- 
culiar or modified use of trinomial names, as at pages 379 and 380, where 
we find “ Saxicola leucomelcena-motiticola ” and Saxicola motiticola-leuco- 
melcenaL in addition to Saxicola leucomelcena and Saxicola monticola , to 
express the relationship of two forms intermediate between the two latter, 
between which, however, he believes “a large enough series will show not 
two intermediate forms only, but an infinite series.” The intent of this 
method of designation is explained in the passage from the introduction 
