256 On the Races and Variation of the Edible Frog. 



varieties striata and nigromaculata in R. arvalis *, and 

 refused to admit it as a subspecies. 



These observations on the, fossorial habits of the vars. 

 chinensis and lessonce should be borne in mind by those 

 who appeal to the behaviour of the Indian R. crassa, 

 compared to that of the typical R. tigrina, as an argument in 

 favour of its specific distinction f. These supposed species 

 offer a perfect parallel to the lines of evolution which can be 

 traced in R. esculenta, as I have recently pointed out %. 



Although we must not expect to find among the species of 

 tbe present day the actual types out of which their allies 

 have been evolved, yet I think it legitimate speculation lo 

 look upon certain species, or certain small groups of species, 

 as a sufficiently near approximation to help us towards an 

 elucidation of the phylogenetic relationships, the expression 

 of which should be the aim of taxonomy. In this sense, and 

 with this reservation, I consider R. catesbiana, Shaw, and 

 R. grylioj Stejn., as representing the most primitive forms of 

 America and Eurasia; the species that cluster round them, 

 R. septentrionalis, Baird, R. clamitans, Daud., R. onca, Cope, 

 R. virgatipes, Cope, R. montezunuv, Baird, would be derived 

 from the same stock; they constitute a distinct section, which 

 is perfectly natural, though not susceptible of a very strict 

 definition. From this section we may imagine the one of which 

 R. esculenta is the type to have been derived, and there is 

 Jittle doubt in my mind that the Chinese R. plancyi, Lntaste^, 

 is a connecting form, nearly allied to, but in most respects 

 less modified than, R. esculenta, both having been evolved 

 out of the same ancestor, possibly related to the Oligocene- 

 Miocene R. meriani, H. von Mey. The chief distinctive 

 features of R. esculenta compared to R. plattci/i reside in a 

 reduction of the nasal bones, the more obtuse fingers, and the 

 very peculiar external vocal sacs. By what steps this last 



* Such modifications represent varieties only in the sense taken hy 

 horticulturists, and should not be given names in scientific nomenclature. 

 Eliminating these cases, I apply the term varietas to every division of 

 the system subordinate to the species, without any further consideration 

 of hierarchy, in order to avoid complicating nomenclature by the use of 

 tri-, quadri-, or even quinquenomiale. In so doing, I simply adhere to 

 the Linnean method which has so long been followed, and is still used 

 by most of the botanists for whose work I have the greatest respect. 

 " Les varietas des systematistes serieux sont les especes de M. Jordan, 



au moins du Jordan des Observationes et du Pugillus Le mot 



vari^te employ^ par les botanistes pour designer une race sauvage laisse 

 peut-etre a d£sirer, metis il joint de la priorite." J. Briquet, Questions 

 de Nomenclature, Bull. Herb. Boissier, ii. 1894, p. 84. 



t Annandale, Rec. Ind. Mus. xv. 1918, p. 03. 



X Rec. Ind. Mus. xv. 1918, p. 51. 



