'SS3-] Receni Literature. lOI 



except 3 referred to Mimocichla, 12 referred to Catharus, and 16 included 

 in Merula. Merula (type Turdus inerula Linn.) differs from Turdus 

 (type Turdus viscivorus Linn.) only in coloration, and chiefly through the 

 sexes being in Merula unlike in color when adult. The name Merula 

 is thus held to be untenable for any species of Nortti American Thrush, 

 nor are any -'generic" names other than Turdus recognized for any of our 

 species, even (excepting Planesticiis) in a subgeneric sense. 



In regard to subspecies, or geographical races, Mr. Seebohm is emi- 

 nently sound in theorj', but, as we shall have occasion to notice later, is 

 strangely illogical in his manner of designating such forms. 'Tt is also 

 due to the student," he observes, "that some explanation should be given 

 of the way in which conspecies [for this word he acknowledges his indebt- 

 edness to Professor Schlegel] , or forms between which the difference is only 

 subspecific, are treated in this volume. In the previous volumes of the 

 'Catalogue of Birds' subspecific forms are recognized. This is an im- 

 mense stride upon the hard and tight system of previous English ornith- 

 ologists who refuse to acknowledge the imperfectly segregated species 

 which undoubtedly exist in nature, because forsooth their binomial system 

 of nomenclature does not easily lend itself to their discrimination. The 

 American system, clumsy- as it is, has undoubtedly the advantage of being 

 far in advance of the old mode. ... It is very important that no mistake 

 should be made as to what constitutes a conspecies. Two forms may be 

 very closely allied ; but if the difference between them, however small it 

 may be, is constant, and is not attributable to age, sex, or season, the 

 probabilities are that it is a specific difference. On the other hand, if the 

 two forms are so closely allied that they interbreed and produce fertile off- 

 spring, which again interbreed, we may draw two inferences — first, that 

 the difference between the two forms is only subspecific. and. second, that 

 between the two extremes mvist be an infinite gradation of intermediate 

 forms. If the two forms have different areas of geographical distribution 

 (which is usually the case), the intermediate ones will be found where the 

 two areas overlap. If, from any cause, the species should be exterminated 

 in the overlapping areas, and the causes which produced the variations of 

 the two forms still continue, the peculiarities of each become emphazised, 

 until they become so far separated, that should their areas of disti-ibution 

 again overlap they will nevertheless not interbreed, and the two species 

 may be considered to be completely segregated. Under these circum- 

 stances, I have preferred to retain the binomial nomenclature for each of 

 the extreme forms, reserving the trinomial name for the intermediate ones, 

 uniting the two specific names by a hyphen, and placing the name of the 

 bird first which it most resembles" (pp. ix, x). 



In reference to the above, it may be said that the author's position, as 

 here stated, in respect to subspecific intergi-ading forms (or conspecific, as 

 our author prefers to term them) is a pretty fair statement of the ground 

 taken ten years since by nearly all our leading American ornithologists, 

 and from which basis they have since worked. It is this view of the matter 

 that has given rise to our system of trinomial nomenclature for subspecific 



